I think that depends on what that want. The ATH might get them their personal moon. The ATH might be all they need to get that 15% gain on their last trade. The ATH might actually be the ATH.

It's true gut feelings can cause you to make mistakes, I did that yesterday, but that doesn't mean that selling at or near the all time high is a bad thing every time.

My personal goal is 10% profit per trade. I set my sell to 10% higher than what I bought (accounting for trading fees of course). If that means at or near the ATH, so be it - the other part of my strategy is to not get greedy by hoping for 20 or 30 or 300%. Doesn't mean I don't try it sometimes, but that's almost always when I get burned.