justinnk parent
What you suggest seems plausible, but there is a very good counter example. Overleaf is also managing well by relying on the open-source LaTEX. What drives people to subscribe is not the typesetting itself, but the ecosystem around it (collaborative editing, version management, easy sharing, etc.). You can make money with those and still have the rendering free/open-source. I believe a similar thing is/will be true for Typst as well.
That is a bad counterexample. There is a world of difference between the main devs offering a paid service and some unaffiliated company offering services.
In principle, having a reliable source of funding for typst is great. However, as a journal this would make me hesitant: what if down the road some essential features become subscription-only?