Rummy does involves the cash factor but not every rummy game is played with cash. If you are an amateur player and have just joined a rummy website, you will be welcomed with some bonus cash with which you can join a cash table for free. Also, some websites host freeroll tournaments in which you can join for free and win real cash. But, as with every other game, upgrading needs you to pay. So, if you want to win big, you need to deposit cash and play on cash rummy tournaments.
This myth is often carried by players who spend most of their times playing games on mobile. In online rummy, you can use virtual money/chips for practice games and real cash for cash rummy games, tournaments etc. Nowadays, most of the online rummy websites have launched their own version of mobile rummy apps in which players can play with cash instead of chips.
It is often said everything online is not so safe. So, when it came to online rummy also, people made a myth saying it is not safe considering the cash involved in it. Although, it is unsafe to use your details in online platforms, you can trust websites that are licensed and hold a certified payment gateway.
Tipping your dealer between the games has nothing to do with your cards. The cards you get entirely depend on the luck and the way you play with them is on your skills. So, next time you play rummy or any other card games, use your cash/chips as entry fee to next game rather than spending on dealer.