Quoting these here from PC Bargains as Epic Store is relevant to this discussion.
I also remember someone pointing out their install of Subnautica was wiped after uninstalling the Epic Store, but I can no longer find their post; let me know who you are and I’ll add your quote, too.
Concerning the Twitch client:
I’ve posted this elsewhere, but it’s more on topic here:
Additionally, Twitch uses a protocol handler to launch games, like Steam; just try and create a shortcut to the program, to see how it works. Except, Steam does this because it has to accommodate for games that have DRM and thus need the Steam client running to start. For the time being, the games on Twitch are DRM-Free (don’t need the client), but IMO this would be a pretty weird coincidence, instead it foreshadows a plan to add DRM.
Mind, it does make sense, as it’s next to impossible to run a competitive store without DRM (sadly). But still, you may want to back up those games while they still are unencumbered, if you care about that.
PS, almost forgot. The Twitch client also does auto-update formally, meaning that updating Shadow Tactics took me more or less as much as downloading the whole game again.