I think that’s wise. It depends on the intentions I suppose. If you’re looking to make a MMO-style game that’s really fun and engaging and pays you (a sci-fi future I’m looking forward to), then you want more immediate rewards. Delayed mana payouts could give you time to filter out cheating. But when I imagine myself approaching some random OSS project, with an aim to make a living from that, an emphasis on all-time cred make more sense. Where you’re new and learning, paying your dues and “interviewing” with the community, it makes sense you wouldn’t get paid much. Indeed, the community is likely investing in you. But you also want a clear path ahead of you to sustainable income. Long-term payouts offer that, and also smooth out your income stream once it starts coming in. If the leaderboard moves slowly but surely, rewarding real commitment and value added, I think that will be pretty engaging also.
In the end, I keep coming back to this ratio as perhaps the most important variable to tweak. And one that may vary by community, and perhaps over time within communities. E.g. maybe we want to do a “recruitment push” to attract new contributors. Or, inversely, perhaps you want a more conservative “monetary policy”, where people are incentivized because they know that if they really commit and work hard, they’ll have mana “residuals” from their work into the future, and a greater ability to jump back into the project down the road and earn meaningful cred.