It is definitely a risk to integrate with any other company. WHY? If that company has a problem your customers will not know or CARE. What your customers will know is your SaaS app was not working.
Now. if you are starting up you have to weigh the time/cost to integrate and build yourself. Risks? Pros/Cons?
If the integration can be done quickly and for low cost you can plan to build your own later and you will also have data telling you if this integration is wanted/needed.

Hope it helps some.