I believe that you truly hold this attitude now, but your response could literally be the preface for every "our incredible journey" post ever published.
Hi – Miguel here. That is totally valid point. I also think this objection stands true for every dependency of your technical infrastructure. This is the kind of decision you have to make, assessing the risks on a case by case basis. I believe no dependency is 100% safe. It can happen to any given service, from companies like Heroku, MixPanel or Segment to the smallest open source library you rely on.
Obviously I think the benefits of outsourcing your in-app subscriptions to us is well worth it, based on our experience and the engineering time you will be saving, but I might be biased :)
I think we just need build trust in the community. That takes time and I accept that.