The only games I have 1CCed you probably guessed it, was Galaxy Fight and Waku Waku 7 only to get that highscore for an online leaderboard (maybe some other fighting games like Garou, AOF3 cant remember). In general I am not a fan of 1CCs for two reasons.
Alot of people are stuck with their arcade games where you can credit feed trough the entire game without any skill, or they go to the other extreme of clearing the game with only 1 credit. The AES is just a great middle ground where you can actually claim you beat an acrcade game with its dedicated AES mode with things like limited credits and feel acolplished without going to the other extreme of dedicating yourself with a 1CC.
Almost all AES modes are beatble with a memory card on 1 player only. Even in Crossed Swords I am came really close with half a bar on the very last boss remaing (should have turned controller 2 on tbh lol).
I have beaten Top Hunter, all the Beat Em Ups, Aero Fighters 3 this way on P1 on my AES. Fighting games, puzzle games are pretty balanced anyways with a memory card. And lets not forget about Pulstar, Last Resort or Magician Lord who force you at 1CC level of gameplay anyways. Thats one the best things when playing on the AES for me, its more than a glorified super gun like some people say. I still have not installed a Unibios and I am tottally fine with just AES mode.
And the other reason: it would also be pretty boring ending up with all this stuff that you spend so much money for but you can beat everything in 1 credit, looking from a collectors perspective. Alot of skill of those who do arent even coming from their normal game setup but alot of performances are studied with save states playing roms on PC, alot of 1CC people have admited that.