Lack of usable support from a lot of access points and management systems. Do any of the major multi-AP systems support it? UniFi has no support. I don’t think any of the Ruckus products support it.
(Also, “push the button” is a bit of an awkward concept with multiple APs.)
edit: it’s also a disaster due to a proliferation of crappy client devices that more or less require it.
I see. I'm using a normal router in bridge mode as an extender and that's been working well enough and comes with WPS built in so for instance, I can turn it on there if the printer is closer but of course it would be nice to turn it on in one place and have all the extenders have it on as well.
(Also, “push the button” is a bit of an awkward concept with multiple APs.)
edit: it’s also a disaster due to a proliferation of crappy client devices that more or less require it.