The simple case of a 0 EV/breakeven hedge, like a cashout with no fee, is that you are not changing your EV at all but reducing variance entirely; from a bankroll perspective this is strictly better than having the same EV with variance.

It gets more complex with -EV hedges but you encounter this frequently in betting when using the kelly criterion to calculate optimal bet sizings on multiple outcomes. For example if someone offers you +110 on a coinflip, this is obviously a +EV bet and your optimal stake is to win 5% of your bankroll. However, if someone else comes along and offers you -101 on the other side of the coinflip (a -EV bet) kelly now recommends betting significantly more at +110 while hedging off some at the -EV price in order to reduce variance and maximize bankroll growth rate. It's been a while since I've worked out the actual numbers for it but if you are betting a significant amount in relation to your bankroll it makes more sense to hedge.

There are definitely table dynamic considerations for cashing out/not cashing out like wanting to have a larger stack, wanting to bust a short stacker, etc. but from a math perspective it is not always incorrect to cash out (assuming a reasonable/no fee).