Vivek Sadh published a short post which illustrates the few steps necessary to integrate stripe as payment solution for a Grails Application.
It is really easy to integrate Stripe. I integrated Stripe a while ago in wirio.com (a grails 2 webapp). Moreover, if you are selling non digital goods. Stripe could work really well for a project which involves Android/iOS/Web platforms. They have SDKs for both iOS and Android.
As far as I know Stripe Grails plugins has not been yet ported to Grails 3.