Aotearoa / New Zealand

PoE adds a bunch to the cost, on pretty much any type of switch at any level. On some Enterprise gear for a 48 port switch it can sometimes be another $1k. Sometimes it'll come down to how many ports provide power, and what PoE standards they support. The newer, higher voltage standards typically will cost more. But especially in Enterprise, PoE gives huge flexibility, mostly for Wireless Access Points these days, but used to be that every desk would have a phone powered from the switch as well.

Anywho, other than that; there really isn't a massive difference between the two. Both will need something running the UniFi Network server for initial setup and management of them. It'd be an interesting experiment to see if they just worked without it though. Their management IP is usually a static in the 192.168.1.0/24 network and they default to using VLAN 1 for everything unless otherwise configured.

Alternatively you could meet in the middle and go with the Edge series from Ubiquiti, eg: https://www.pbtech.co.nz/product/SWHUBI31306/Ubiquiti-EdgeSwitch-XP-ES-5XP-5-Port-Gigabit-Manag

These don't require UniFi Network, you just log onto a web GUI to configure them which can be limited to only the MGMT port, and this particular model also does PoE, though probably only the older standard, not PoE+. I have one of them (the older version called ToughSwitch) and its been great. I'm pretty tempted to swap it for one of those Flex Mini's though - as that way I can manage it from my UniFi setup rather than having to do it manually.

Actually just an edit to clarify the adapter/splitter... Back in the day you could buy a Hub, that's closer to what I would call an adapter/splitter. The way they work is it effectively just turns one port into x ports, they're a very dumb usually completely unconfigured device. But on a hub, all ports share the same collision domain so overall performance is weakened especially if you have a lot of devices connected to hubs.

In a switch each port is its own separate connection, and it'll hold its own MAC address table to know how to get to things at layer 2. The difference is a hub is a bit like a party line (back in the analog days) where you could end up having one device talking over another. Whereas with a switch, every device has their own private line back to the cabinet.