Yet customers will license Sage CRM over other options simply because it is (natively) integrated. And because they are looking at the true reasons for having a CRM, as you mentioned @PeterWolf , the extent of the integration is not that important as long as it is supported by Sage.
This is also a reason customers have decided on Endorsed solutions over alternatives that may be better. The perception is If they are endorsed by Sage, they must be better. It works for me, but I always point out the alternatives and let them decide. My exception is shipping. I simply tell them StarShip has a better track record, we have many clients on it, and we can support it more easily.