@jdibber - No one has really answered you regarding the core differences of consumer mesh vs wire-first APs on wired backhaul, so I'll take a stab at it.
The first set of differences are specific to the wire itself:
1) PoE - Almost all wire-first APs are designed with PoE as the optimal power source, for all the obvious reasons. I don't know of a single consumer mesh product that supports PoE; consumers are more apt to plug-power their nodes I guess, but for anyone wanting the ultimate in discretion or radio placement flexibility, PoE is the way to go.
2) Multi-Gig / LACP - Apart from a low number of AiMesh-compatible Asus all-in-ones with 2.5GbE LAN ports, practically zero consumer mesh systems offer multi-gig backhaul, and none support LACP, although that will probably diminish over time in favor of multi-gig on a single wire. Regardless, neither are really glaring omissions in most home networks, as you don't usually have enough client data per AP to saturate 1Gb, nor do most homes have access switches capable of multi-gig. But the point remains, it's a lot more available in wire-first AP products.
The following differences are irrespective of backhaul method, but are still as important, if not more so. In rough order of importance:
1) Seamless Roaming - In consumer mesh, most implementations of 802.11r/k/v, plus any assisted control plane intelligence (if you can even call it that) is somewhere between completely missing and almost-good -- with the exception of a very few select products, Eero being one of them.
Controller-based APs tend to do this better; SMB gear by a fair bit (Omada, Cisco WAP), enterprise-grade gear by a
lot (Aruba, Ruckus, etc.).
2) Fronthaul Channel Usage - APs can actually be set to use different, non-overlapping channels for 2.4 and/or 5 Ghz
fronthaul (endpoint) broadcasts. No consumer mesh that I'm aware of allows for that (regardless of the backhaul connection method), which limits airspace usability and efficiency, especially when deploying more than two or three AP/nodes.
3) Traffic Control & Management - Just going to group all of these together. Bottom line: if you're at all serious about segmentation, management, AAA and/or policy-based anything, APs are your only option (VLANs, QoS, ACLs, 802.11x/RADIUS, SNMP, etc.).
Beyond that, some comments:
IMO APs and "mesh" are pretty much the same thing. [...] Can't run a wire? Then you connect the AP to the router over WiFi. [...] And that's all that mesh is. But ... with Klueless-friendly software.
I'm glad you added the "but"-with-software, as vanilla repeating between standalone APs is very different than real
mesh, especially multi-point, multi-route mesh, which is an entirely higher-order beast.
if [mesh is] tri-band it'll dedicate one radio for the back haul and the other two for clients.
Apology for the pedantism, but not in all cases. Tri-band Eero Pro uses a mix of all radios for fronthaul/backhaul/split-duty depending on RF environment and traffic flow requirements -- one of several reasons why it's by far the best consumer mesh code base out there. And I would expect more products, both consumer and business, to start adopting more real-time radio re-purposing as mesh software standards mature.
With APs you can mix and match vendors.
While technically true if all one cares about is L2-unaware repeating/bridging, I recommended a single controller-based brand/ecosystem, in order to enjoy seamless roaming, central management and uniform scalability -- all things that have become more-or-less synonymous with multi-node wifi these days, and things that I'd argue are worth investing in, especially if you have a blank slate to start with.
Hope that helps to clarify things a bit for you
@jdibber.