One of the most obvious examples of the problem with this approach is that they're shipping previous generation servers on Day 1. One can easily buy current generation AMD servers from a number of vendors.
They will also likely charge a significant premium over decoupled vendors that are forced to compete head-to-head for a specific role (server vendor, switch vendor, etc).
Their coupling approach will most likely leave them perpetually behind and more expensive.
But there are advantages too. Their stuff should be simpler to use and require less in-house expertise to operate well.
This is probably a reasonable trade-off for government agencies and the like, but will probably never be ideal for more savvy customers.
And I don't know how truly open source their work is but if it's truly open source, they'll most likely find themselves turned into a software company with an open core model. Other vendors that are already at scale can almost certainly assemble hardware better than they can.