One problem it has is that it can be REALLY slow sometimes. Like any turn based strategy game, map size has an exponential effect on how long a game takes, but the mechanics of wesnoth lean a lot more towards larger maps.
I’m mostly talking about multiplayer though. For singleplayer there’s about a hundred million campaigns to play so you could probably play it forever.
I’ve been playing it sporadically over the past 10 years and I’d say it’s a lot of fun! Very easy to get into, even for people with little strategy experience. The mechanics are clear and not overly complex; for beginners and intermediate players I feel like it’s just the right balance.
It also runs on pretty much anything (as demonstrated^), so I like having it installed and playing a short skirmish for 20-30’ if I’m bored. Alternatively, there’s plenty of decent campaigns, and a lot of fan content (and a map editor if you want to try your hands at it).
I’ve only played it a computer though, so not sure how well the interface works for touchscreens.