As a dev who has used both React and a couple of native desktop UI libs, I get a fair bit of pushback on the whole Electron / app-in-browser idea. The primary concern seems to be performance, although I'm picking up an undercurrent of fear that the web stack could swallow the native realms, even if it is technically inferior, just because of the sheer inertia behind it.
In a way, Electron is a threat to the culture of the pure-native devs. Everything they know gets subsumed and disappears below the browser, and a horde of outsider devs come rushing into the native app space, with little awareness of the nuances of specific platforms and their communities.