Ubiquiti makes hardware designed more for business use...SMB and Enterprise. Not really aimed at residential. Residential wireless...having a web admin page on the local device will suffice. Typically just a combo router with built in wireless (like a wireless router) is all that is needed there.
For businesses..typically you have a dedicated router/firewall...and then you have multiple access points. Ideally for larger networks with multiple access points...you want a centralized controller to manage all of those access points...so you can monitor performance, adjust as necessary, tie them all in with a universal configuration, change SSIDs, VLANs, guest modes, security passwords, perform firmware upgrades from a single interface. For larger setups...monitoring, tweaking/tuning, finding out causes of problems, finding heavy bandwidth users, seeing if you need more APs due to too many clients....frequently looking at the controller and monitoring it is important. If you look at larger business wireless setups...you'll find a centralized controller is commonly used. HP, Cisco, Meraki, Ruckus, CloudTrax Open Mesh, etc..they all have controllers. Many of them are dedicated hardware units...like a 1U rack mount appliance.
For those of us that have many business clients and manage them...having a cloud controller to manage ALL of your clients from one portal is great...since the UBNT controller is multi-tenant (can have many sub accounts...sites).....so we can easily manage all of our business clients wireless setups from one spot.
Ubiquitis controller is pretty flexible....it's free, and you can install it on whatever you want...a PC, a role on a server, a dedicated 1U appliance server, or even your own cloud server like I did for us up at RackSpace.
https://www.technibble.com/forums/t...ix-based-unifi-controller-at-rackspace.61937/