Im currently writing a turn based start game, which will be played in an MMO style (players download clients, central server handling the game logic etc.) and now I need to decide how I charge my players for playing my game, since this will have some implications on how player account handling is going to work.
After looking a bit around, I found two alternative ways of doing this
a) Classical in-app purchase, for which my clients need to be able to take the payment info, send them to my server which then charges the selected amount (using some API like stripe.com) and provides the selected services
b) Account administration and payment via website, and then synchronization between website and game server over some database
Most MMO games I know use the website approach (b) although I assume that in-app purchase (a) is faster and easier for my players and will therefore yield higher conversion rates.
So, my question is: Are there some major problems (security, paperwork) or drawbacks (complicated to implement) with in-app purchase I overlooked?
Im not doing a mobile game (full desktop) and Im from europe, just in case this information might be needed.