It's half-height (fits in "slim" desktops, those media center PCs, and in a 2U server without having to turn it sideways/use a riser), and barely longer than the PCIe socket. Phoronix has a picture with a full-height bracket which maybe gives a better point of comparison: https://www.phoronix.com/review/intel-arc-pro-b50-linux
(A half-height single-slot card would be even smaller, but those are vanishingly rare these days. This is pretty much as small as GPUs get unless you're looking more for a "video adapter" than a GPU.)
Agreed. I have an A40 GPU in an epyc system right now specifically because it's a single slot card. I did not pay for gobs of PCIE expansion in this system just to block slots with double wide GPUs. Sure it can't do the heavy lift of some beefier cards but there is a need for single space cards still.
(A half-height single-slot card would be even smaller, but those are vanishingly rare these days. This is pretty much as small as GPUs get unless you're looking more for a "video adapter" than a GPU.)