It's free so definitely worth trying to see if it interests you. Definitely play on PC, mobile is fine for short bursts but not ideal for longer play sessions.
- - - Updated - - -
New story quest featuring Mona is being added next week, becomes available at AR 38.
https://genshin.mihoyo.com/en/news/detail/6064.
Also supposed to be a new event but no details available yet, https://twitter.com/GenshinImpact/st...157580289?s=20