What Skype are you comparing it to? Skype for business or consumer Skype? If the former, the usual justification is that it is able to be hosted, whereas with Teams you're forced to use MS's cloud. If the latter, then it really is probably just inertia, although I don't understand your point about persistent chat - Skype has had that pretty much ever since MS took over and got rid of the old peer-to-peer chat tech, which was definitely a change for the better. I also feel like on the whole Skype still has a cleaner, simpler and easier to grok UI than Teams, which is why I would always recommend it to join-techie people over Teams if given the choice (and assuming the large team features are irrelevant). The difference between "chats" and "teams" in Teams, and especially the different ways of interacting (threads or no threads) depending on which context you're in, is confusing, and it's annoying that you're always thrown into the near-useless "feed" view on mobile, instead of picking up where you left off. Skype in my experience also has better compensation for microphone feedback and noise cancellation. So in my view there are plenty of reasons - as a consumer user - to prefer Skype over Teams.