Some platforms (like MEXC) are already doing this on selected pairs.
But obviously, it’s not completely free.
You still deal with:
spread
slippage
and funding rates if you’re in futures
So the cost is still there, just not as visible as a trading fee.
That said, removing fees does make a difference. If you’re doing frequent trades or scalping, those small percentages usually add up over time.
I hope that you made this thread for education, but not for advertisement of MEXC exchange.
About these drawbacks you mentioned, they're right and I agree with you too. Exchanges can sometimes give "zero-trading" fee offers for users when they were new exchanges and need to make noise to get users, or when they see that it's good time of cryptocurrency market to waive trading fees in order to increase trading activities of users on their exchanges. Such offers won't last for too long but users must be more careful and cautious if these offers are from new exchanges.
It can be honeypot for new exchanges to get users, get money from user deposits, then make their scam exits.
In addition, there are drawbacks you already mentioned.
Generally, there are many exchanges to choose by filtering their Taker, Maker, Withdrawal fees.
https://www.cryptowisser.com/exchanges/