I looked at the rules and I was wondering why Wong Warp is banned in SMB3. Should it be allowed as Wrong Warp is technically the real Any%? I mean, it’s a Any% marathon not a Any% and no Wrong Warp marathon.

WW imo isn't easy, and I personally think that No WW would allow more runners to do the any% categories rather than work on a difficult glitch.

probably it's because speedrunners discovered this trick after the Marihour Challenge was born! i'm not entirely sure but maybe this is the reason!

No. WW was discovered YEARS ago. Marihour was made in 2016.

We generally don't allow ACE (Arbitrary Code Execution) categories for the multi-Mario games. Those are SMB3 Any% and SMW 0 Exit. We put a sub-category on the All-Stars leaderboard a few years ago that did allow ACE and not one person ever put up a run after a couple of years, so we just removed it.

This next statement is just my personal opinion, but I feel like throwing a couple of games with a credits warp in with the rest of the games where you actually progress and defeat the final boss feels kinda silly and ruins the flow.

yeah roop's explanation, especially the second paragraph, is why darbian used no ww in marihour and why it's in other any% multi cats, though if you really want to do a WW/ACE marathon look at decathlon any%