GoDaddy had to do something. Switching to GoDaddy for Managed WordPress was great in the first year, but they re-tooled plans and sent their most lucrative customers into sky-high plans that made no sense.

Moved back to Dreamhost, and their Managed WordPress, and only regret not doing it sooner.

If I had to guess, I'd say ManageWP was meant to be integrated as a relaunch of GoDaddy Managed WordPress. Let me know in five years when the dust settles.