I prefer to donate time. I’m now president of one local non-profit (in addition to my paying job), and a regular participant in another. Sometimes I’ll donate supplies that we need, but never money.
If a time comes when I have little time and a lot of money, maybe I’ll switch. Donors are necessary. But I know that we need hands more than dollars.
You’re arguing that the actions of individuals have no impact on the collective actions of humanity, the sum of 8 billion individuals.
Similarly, you probably never had a conversation where someone said “Gee, I’ll stop burning fossil fuels now!” But when you use public transportation, or patronize businesses on foot, policy makers are motivated to continue supporting such options. Not for you personally, but for you and others like you.