In land-based casinos, particularly in the US, it’s customary to tip the dealer if you win. If you’re playing at the lowest stakes, it’s understandable to not tip, as any tip may have a noticeable influence in your EV. That said, even for bets of $5 or $10 per hand, tipping a few bucks after a number of consecutive wins is widespread practice. Because they nonetheless have benefits even when you’re not guaranteed to beat the sport.