Yeah it's a little bit payment integration but being aware of tax rules, ironically in the UK this got slightly less complex after Brexit , and mostly world wide sales will fall below tax thresholds (e.g lots of places it's $100,000 of sales before it all kicks in). But you either have to know all this or pick something. Now there are providers who act as "merchants of record" and do a lot of the work, Stripe has more advanced tax tools so it's not as bad as it used to be, but you have to know all this when really you just want to write more Umbraco code.