If you're in a position where you have a small number of AP's (less than 5) the ubiquiti product may appear to be overkill.
An office of 30 people sharing 3 APs will encounter problems even if those same APs would have worked just fine for a family of 4 living in the same space.
I've even found this to be true in a residential setting with consumer APs, where reducing the number of devices (by plugging into wired ethernet things that don't often move, such as media players and printers) tends to improve range and throughput for others, without adding more APs.
I'm not suggesting that there's necessarily value in "managed", but your parent comment was about the Ubiquiti product being overkill, which is a much broader statement.
The GP certainly advocates for management, but that's neither the primary value delivered by the overall product, nor the majority cost (even with a single AP). IIRC, this may not hold for competitors, such as Ruckus, where even the lowest-end "controller" is quite pricey.
> wifi should function without the need to phone home.
AFAIK, Ubiquiti's products can be run standalone, only requiring management software for initial configuration.
This is correct. I only power on the controller VM when I want to make a change. I do think a few features, like the captive portal require the controller to be online.