A big part of that is having payment methods on file so the transaction is as frictionless as possible.

If somebody has never purchased an app, setting up payments in the app might be seen as “too much work, especially just for this one app”. But once you get the payments in there, each subsequent 0.99 payment is painless

at least for some of it what's nice is that you are getting exactly what you paid for on the tin, and most importantly you are not getting locked into some god-awful subscription with a cancellation process akin to pulling teeth.

the urge to buy goes down if the subscription is cheap enough ($.99 songs versus $12 a spotify subsscription) but having been through my fair share of attempting contract cancellations this isn't surprising.

It'd be interesting to see open data about this.

My understanding is games with microtransactions optimise for "whales", people who spend inordinate amounts of money. While the majority of users don't pay anything, or at most very little.