A commercial offering is not, in itself, a plan to increase user adoption. It requires a plan to increase user adoption and is therefore probably not the best answer.
You could reply that in the past months you’ve had close contact with (i) the Gitea project which has 30,000+ stars on GitHub and 100M+ downloads on docker hub and (ii) Codeberg which hosts 10K+ projects. They show excellent prospect to deploy, integrate and distribute mCaptcha and would be the primary adoption driver for the immediate future. You can also say that you will actively look for use cases in need of the particular features of mCaptcha within the projects already funded by OTF.
The first paragraph should probably be moved down. You could initiate contact with Tor immediately and report that you have done so.
I find your reply otherwise well articulate and straight to the point. I’m also optimistic about your chances to get funding because it looks like the problem is well understood by the reviewer and within the scope of what OTF is looking for.