I will say that isomorphic [1] JS apps are really fun to write because with well abstracted APIs, the back end and front end don't feel like a discrete API and a discrete front end, but one entity that communicates via asynchronous function calls. For instance, working with firebase functions just feels like working with a local async function. But that's really a minor benefit to the fair criticisms you give.

[1] Whoever came up with isomorphic really liked their fancy math terms. Personally I'd have chosen automorphic, as it's all contained inside JS.