[s_tec]

If your team has invested a lot of time & energy into mastering the Javascript ecosystem (including things like Typescript), it makes sense to use the same language on the server side as well. Server machines are cheaper than good developers, especially if you can share resources between the backend & frontend.

As for Deno specifically, it's definitely closer to the "browser" way of doing things than Node is, which is super attractive. The main reason to stick with Node is the huge library ecosystem, but Node itself feels kinda weird & old, since the language has moved in a different direction while Node has remained stagnant (poor support for promises & ES modules, for instance).