WGU is accredited. If you are sufficiently motivated, it is fast and cheap. It doesn't require you to move or to quit your existing job.
I can't speak to the motivations of the person considering it, but perhaps s/he only needs to check a "do you have an MBA?" box on an application to be able to move forward in their career.
WGU is a competency based school. So I can finish my MBA from anywhere between 6 months - 3 years. On brick-mortar schools, you are limited to 3-4 classes per semester.
I have been looking at WGU for an online MBA degree. Reviews are just scattered everywhere from Reddit to affiliates websites.