It's not fascination, rather understanding of cricket (or lack of it).
A spinner whose stock ball is going away from batsman always is much, much more potent for penetration (wicket taking ability), because he can bring many more wicket taking variations in his plan - remember, there are 10 ways a batsman can be out and 7 of those goes in bowlers' credit. A spinner who takes the ball away can bring slip catchers in play, can bring WK for stamping, can bring cover cordon for mis-timed drives, can bring short squire fielders (point, gully, short 3rd man) for miscued cuts. On top of that, he becomes twice effective if he can bring the odd ball in or held it's line without changing action much - it brings LBW, Bowled & Short Leg, Short Cover fielder in play. For SLAO spinner that tool is his armer, for leggi it's Googly or Flipper (Or something Warne used to call slider). The best in the business could drift inwards/outwards through air and then turn it other way after pitching - best I have seen ** Bedi, Qadir and Warne, who would drift in air towards right-handers leg and held line between sticks or whistle pass outside edge after pitching, while Qadir could drift away before a BIG Googly coming into wickets.
Some effect could be achieved by Off-spinner as well with big inward turners, but for one particular cricket Law - to get LBW, while playing shot batsman has to be stuck on line. Theoretically, unless batsman is deliberately padding up, an Offie should never get LBW against right hander, unless he beats the front pad and hit back leg - by the law of mechanics, a turning off-spin can't hit front leg in line and doesn't miss leg stick - the margin is only 6 inches. Against decent spin players, for an Offie on a good wicket, only realistic option is teasing batsman's patience by keeping it tight, and may be bring the 3 leg side catchers in play. But, there is also a problem - after Body-line, cricket rule was changed and now one can keep only 2 fielders behind Leg-umpire's line; so an Offie can only keep two of four such fielders - leg slip for thin edge, short leg at 45 degree for top edged sweep, back-ward squire leg for miscued flicks and deep leg boundary for solid hits.
SLAO spinner (Ala Gohar), will face similar sort of problems against left-handers, but naturally around 75-80% batsmen are right handers, hence Off-spinners without doosra, finds it extremely difficult on true surfaces. Moreover, right handed batsmen can always stress their front leg outside line and keep kicking or sweeping for whole day against an Offie - unless the bowler gets some awkward bounce -it's almost impossible to get a Test batsman out. However, Aussies are groomed on hard, true wickets and their game is dominated by squire of the wicket back-foot shots - a tight Offie can block their bread & butter shots and choke them, hence Offies have done well against Aussies by cramping them on back foot compared to SLAO spinners, whom Aussies play like a slow medium pacer and free their arm along the line.
Coming to Yasir - HE IS NOT A CONVENTIONAL LEGGI. Among top class Leggis, he has the least variations, has the least amount of turn - what he has is extreme accuracy and variation in pace, which works brilliantly on docile UAE or WIN wickets backed by his unreal stamina. Most of his wickets are not conventional Leg-spinners wicket (i. e. Caught behind batsman in arc, stumping or miscued drives), rather he gets among highest % of LBWs on typical UAE type wickets. Also, he bowls flipper almost like stock ball rather than as a surprise element which actually goes away from lefties slightly or keeps straight - but flipper pitched in line will always earn more LBWs against Lefties than right handers because Umpires need not to bother for "pitching out side leg" considerations in that case. Another tactical issue is, Yasir is playing in DRS era - umpires are bold enough to give LBW; I have seen left-handed batsmen get away with plumb LBWs against Qadir's flipper or conventional Leggis. Above all, Yasir is lucky to play in an era when spin play is at it's lowest point probably since 1st World War, hence his stakes are high with so little variation and spin. I can comfortably say that 3 WKs of 1990s - Kalu, Mongia & Moin would have been among top spin players of modern T20 era. These days anyone tacking the ball away from batsman is a hero because of lack of foot-work, inability to read the spin in air or from delivery action and using 3KG mallets called bat, which helps thinnest of edges reach fielders.
Zafar Gohar is a fantastic prospect and easily the best conventional spinner from PAK in last 10-12 years - comfortably a better potential than Shadab Khan, who is sinking by every day because he didn't develop his leg-spin bowling. Had Gohar been picked at the right time, PAK would have won SRL series 2-0, or at least made it 1-1, NZ series at least 2-1 and AUS series 2-0 as well...... and probably would have made a less shameful outing in SAF.
<a href="https://t.co/BqBgwDSavm">pic.twitter.com/BqBgwDSavm</a></p>— Zafar Gohar (@iamzafargohar) <a href="https://twitter.com/iamzafargohar/status/921025322585415680?ref_src=twsrc%5Etfw">October 19, 2017</a></blockquote>
