https://en.wikipedia.org/wiki/Earning_to_give
I have no idea what an "earn to give" charity even does[0]; I assume they just donate to other charities? I'd probably not bother donating to one because I can just donate to a specific charity directly, because it seems like I'm just skipping the middle-man there. Anyway, regardless of the effectiveness of earn-to-give charities, "earning to give" as a personal lifestyle choice seems reasonable, depending on the implementation.
(Alternatively, make a habit of donating time at a local soup kitchen or similar.)
0: Until I read the comment above, of course: "Both charities focus on building the earn-to-give idea into a movement." I would not personally donate to this charity, presuming its ineffectiveness, for what it's worth.