Because it was the best available option in my price range in all other aspects and I honestly don't care all that much where the AP controller for my home network is located. The APs will continue to work while offline and I'm unlikely to even look at the controller interface more than a handful of times a year provided the vendor doesn't do anything that will outright break things. I honestly don't care if it's hosted inside my network or not.

Ubiquiti has a history of poor software releases that break things and now of trying to gloss over a serious security breach. I'm less worried about HPE in that regard.