Even if it's just indirect competition, by giving yourself an advantage compared to others you affect what others percieve as a healthy benchmark for performance.

"Just neopets" isn't an excuse, you could say the same for any online game.

Cheaters even wreck just the scoreboards for some games. You might think a fake score submissions is about the least damaging thing since it doesn't directly effect others gameplay at all, but it still ruins the experience and affects the community's ability to compare and share genuine runs.

Being banned eventually is hardly a punishment, doubly so if they ever sold-on their ill-gotten gains for real money.

There wasn't a hint of contrition in OP's post, and the downvotes I'm receiving suggests that the culture of entitlement is so great now that cheating in multiplayer isn't even seen as bad anymore.