It's still limited to applications that explicitly support it. Maybe there will be a wider ecosystem than Adobe's. But my current preferred reader apps all either have built-in storefronts (Kindle, Apple Books) or are open source (Calibre and Google Chrome, so I can use a Japanese dictionary extension). The former category probably won't ever support LCP, and the latter category definitely won't.

And as for longevity… who's to say LCP will still be around in 10 years or 20? At least Adobe has a big brand name.

At the end of the day, I'll keep using de-DRM plugins to get around those problems, but that's a solution that only works for people who are relatively tech savvy, not your average reader. And I'm not sure DRM will always be as ineffective as it is today.