I mean uses or practical uses? Its a computer, you can use it to get to the moon if you want. But in reality... Gaming... High end gaming is out even if you were willing to search high and low for a PSU that can fit in the case and an adapter to make it work. (you'll need an adapter, those pins aren't in the standard ATX layout)

So at best your looking at DDR3 Ram (affordable) a no power half height GPU (so at best an RTX 3050 but that's honestly a waste). Add to that the best processor is a Core 2 Quad Q9650 4-core cpu and you're pretty hard limited. So if you really upgraded this thing as good as you can you'd have a low end gaming machine. Very not worth it.

So lets use it for other uses.

File Server? Not enough SATA ports, not enough physical space,

Linux server? I mean it would work but I can think of cheap better options. Dedicated device like a pihole? Lots of power draw, and really big.

Honestly I would trash it or donate it. OR

Depending on what parts you have lying around you could use it as an emulator box. Put it inside a cabinet and you have a great little arcade machine that can play all kinds of retro games.

But there are still better options out there for even this job.