It seems to me like the primary benefit of typical EA donors (say, most GWWC members, or anyone giving less than $100,000/year, i.e. the vast majority of us) giving effectively comes from the signaling effects of this behavior on helping to promote a culture of effective giving and effective altruism.
It still seems very worthwhile for typical EA donors like me to donate, since the direct value of my donations is still substantial and there's potentially this even greater signaling benefit on top of that.
That said, as Ben Todd summarizes in his answer, most EAs (i.e. everyone not in the reference class of people who have a nontrivial potential to become very wealthy EA donors) can probably do even more good through various kinds of work that help deploy the large amount of EA funding that already exists better and faster than they can through their modest donations.
Given that, I wouldn't want to encourage a small donor to donate a modest amount at the expense of them putting less time/effort/attention into shifting into a very valuable direct work career that helps deploy existing EA funds faster/better. But, if donating some percentage of a person's typical income helps keep them engaged with EA and thinking about important questions related to how we can all do the most good, then it definitely seems worth doing to me.
If anyone thinks I'm wrong about this, please let me know!
One effect of the new funding, IMO, should be to push individual donors towards giving to up-and-coming causes that are currently adjacent to EA, rather than pumping money into the core areas of the movement. Putting lots of money into the already proven-out causes (like global health & development, AI safety research, etc) is what the big institutional funds will be best suited for, so individuals should seek to complement that by funding more experimental causes and interventions. (Of course big institutional funds also try to make small development grants to a range of up-and-coming charities. But I think it's maybe not their comparative advantage vs individuals.)
This is potentially helpful in two ways:
I explain my reasoning more and list a few examples here, but by definition there are a lot of adjacent / non-core cause areas... here is a giant list of cause candidates with lots of EA-adjacent ideas which mostly aren't yet receiving billion-dollar donor commitments.
See this post by Ben Todd for an overview of where current spending is going, by cause area.