Yes, for transient apps that are only used occasionally or where the user isn't committed e.g. social networks, the combination of sandboxing + no integration/unintegration steps, automatic deletion from the cache etc is really useful. Of course there's no rule that says only web browsers can supply these features. Other kinds of browser-like thing can do so too.
It's also worth thinking a bit outside the box. Although we claim web apps don't have installation steps, that's not really true most of the time. The lack of any explicit integration step ("install") means the browser doesn't know if the user values anything they do on the site. So you have to provide data persistence, and that in turn means you need a signup / account creation flow. It also means you're on the hook to store, replicate and back up any data any user ever creates, even if they only used it once and then never return.
Well, a lot of users really hate creating yet another account, especially if they aren't committed yet. It's tedious, they think you'll spam them with marketing emails and they're probably right, plus they don't want to make another password. Or they make one, abandon for a year, then can't remember how to log in.
You might think that's so fundamental it can't be any other way, but it's really just a side effect of how browsers have evolved. Think about how you might do demos outside the browser. You could just have a trial mode where the app spins up a local in-process RDBMS like H2 that writes the data into the app's private data area (on Windows) or home directory on macOS/Linux. No accounts necessary - just one or two clicks to download+trigger app install, and you're done. If/when the user decides to graduate, then they create an account and the app uploads the data from the local DB to the real remote DB. If they abandon it and don't care, it's not your problem, it costs you nothing. If they run low on disk space the OS will suggest they delete old unused apps at that point and you'll get tossed along with the rest.
Mostly though, this is about making developers more productive. If the primary determinant of your success is feature throughput and not shaving a few seconds off your onboarding, e.g. you're making specialised apps, internal apps, enterprise software, then optimizing for better dev environments can make sense. Installation just isn't that bad.