The key thing is that it's a sign that you're effectively going to be outsourcing a complete userland to them, which means you'll be much more dependent on the

The key thing is that it's a sign that you're effectively going to be outsourcing a complete userland to them, which means you'll be much more dependent on the vendor for security updates to anything their code depends on as well as their code itself. Whether or not this is a good idea depends on your situation and their level of competence.