All the marketing for this advertises it as a desktop computer. What's the appeal of this compared to a cheaper and more powerful N150 NUC, or a used mini PC if it's for personal use where you just need one?

A N150 has about twice the CPU performance, hardware video decoding that isn't crippled, and much more software built for its architecture among other things.

And the N150 had mainline linux support from day one, whereas I'm not sure if there's proper support for pi5-family devices in a released mainline kernel even now, two years after the launch.

They used to do an good-to-adequate job of linux support, but nowadays they seem rubbish at it. Nobody wants to be stuck on a downstream kernel full of cobbled-together device support that's too poorly-written to upstream.

The appeal is the form factor, really. A decent amount of compute (not amazing, but decent) built into a decent mechanical keyboard (jury's out, but I'll believe the sales pitch until shown otherwise) is unusual.

It requires a separate keyboard, which means more space usage and more cables. And not sure, but I think the N150 has a fan, so more noise.

Right, this thing is priced from an earlier (pre-BeeLink) era. There’s just so much more you can get for $200 nowadays, right off Amazon.

Software support could be one if N150 wasnt x86 from intel.