What you need to know about Tor is that the network consists of clients and relays. Clients are mostly users with browsers. Many of which disable JS, because JS can de-anonymize sometimes. This breaks some websites.

Previously I could not visit CNN.com via a JS-disabled Tor browser, but now I can type https://html.brow.sh/https://edition.cnn.com/ and Viola! (Well, it's still a little crippled but much better than a blank).

So, brow.sh benefits JS-disabling users. The Tor project receives donations and they dedicate them to enhance Tor. And, I think this is a neat enhancement. While I am not totally familiar with their money handling, I wouldn't be surprised if they are willing to funnel some of the funds to various side projects that improve the Tor experience.

In summary, the use case you advertise is minimal bandwidth for clients, but you missed the privacy use case, which someone may want to fund.

Edit: grammar fixes.