The donating of gas fee won't be that sustainable long term especially if the token is having lots of transactions. Some could even abuse it by deliberately/unintentionally draining the reserve with unnecessary transactions except ofcourse the token devs or site owner make it one or few transactions per unique address or something.
It's good you considered doing something about it. You still could try other interesting ways people/things that can't afford it can send token without bothering about gas fees