Its not

Go price out a used 1l form factor PC.

After you buy a case, and a real disk, the pi, cost savings is gone.

Meanwhile you can pick up a used 8th gen intel 1L form factor for about 100 bucks. You can pick up one that will take a PICE card for 150ish bucks, with remote management.

The 8th gen or better intel has all sorts of extra features that may make it worth while (transcoding/video support).