Maybe that's just me but flexible-location on the other hand to me suggests that the person is constantly on the go, e.g. in a café.
Given the shitty internet situation (might just be here in Germany though) and background noise anywhere that is not the office or home (which seems to be still bad in a lot of cases), that doesn't seem too desirable of an image. Those factors are what cause the location in "flexible-location" to be home 99% of the time for me (and probably many other people).
"Flexible location" also opens up a bunch of potential tax issues if people are spending a lot of time working from another state or another country. (Surprisingly, the former can be a bigger issue than the latter assuming visa limits are being observed.)
Given the shitty internet situation (might just be here in Germany though) and background noise anywhere that is not the office or home (which seems to be still bad in a lot of cases), that doesn't seem too desirable of an image. Those factors are what cause the location in "flexible-location" to be home 99% of the time for me (and probably many other people).