Lolwat? You literally yourself chose one format over the other right in this very thread. Maybe say that to yourself?
Alternatively, if you are done being silly,
I literally explained why in the 2nd point itself.
Test cricket requires far higher skill because it tests a batsman in much more complete way than white ball cricket.
Smaller spells means a batsman is able to get away from the most threatening bowler without standing up to him.
No slip to worry about for most of the game means countless edges go unpunished. The room for error is much smaller in test cricket.
Fielding restrictions, luxury of 2 balls (ie barely any spin) , no pitch deterioration give the batsman far less to worry.
The only point in odi's favour is the runrate pressure which is only occasional.
There isn't a complete overlap of skills if you want to find silly logical traps and indeed, certain odi innings can be more difficult than scoring same amount in tests but if we want to make a general statement, there are sufficient reasons to say
that test batting requires a higher level of skills.
If you are done waffling and you are done with your mental gymnastics, you’d realize that I didn’t ask a difficult question.
If Test cricket requires a far higher level of skill, then why do a lot of batsmen who have mastered this higher level of skill unable to perform the so-called lower level of skill?
If Test cricket was actually harder, every successful Test cricket would have dominated ODIs and T20s.
The bottom-line is that Test cricket is not harder. It is simply a test of different skills and characteristics.
If you have those skills and characteristics, you will do well in Tests. If you don’t, you won’t.
Similarly, ODIs and T20Is require a different skill-set.
The truly great batsmen are the ones who have the versatility to meet the demands of both red ball and white ball cricket.
Again - Test cricket cannot be harder than white ball cricket if a lot of successful Test cricketers are failures in white ball cricket.
Is the reverse true? Sure. So what does that mean? It means that the only logical and factual conclusion that we can draw is that no format is harder than the other. They simply test different skills and attributes.
If you have Test-specific attributes, you will be a good Test player. If you have LOI-specific attributes, you will be a good LOI player. If you are a complete batsman, you will excel in all formats.
As far as the prestige is concerned, it is a completely different argument. Test is the purest format considering it’s stature throughout the course of the history of the game cricket, so if you want to say that it is better to have Test cricket skills than Limited Overs cricket skills, that is perfectly fine.