I really like this idea, and I think WeChall has a very unique chance to make certificates more meaningful than a simple points-based badge.
What makes WeChall special, in my opinion, is not only the score itself, but the fact that it connects achievements across many different challenge sites. It also reflects long-term dedication, category diversity, and the experience of gradually climbing through the challenge ecosystem.
So maybe a WeChall certificate could focus on things that only WeChall can really represent: multi-site achievements, long-term progress, curated category paths, and possibly some kind of mentor or admin verification for higher-level certificates.
I also think it would be important to respect the alias culture of the community. Certificates could use the nickname by default, with an optional real-name field for people who want to use them professionally. A public verification link connected to the WeChall profile would help make the certificate trustworthy without forcing users to reveal more than they want.
In that sense, a WeChall certificate would not just be proof of points, but proof of a real journey across many different challenge worlds. I think that would fit WeChall’s identity very well.