Lots of people, including myself, case-mod them to fit standard or extended ATX boards. The workstation style flow-through cooling can be really good.

There are guides online, but it’s easy to figure out. The cases are worth money to people who want to do this.

Grate some cheese?

It is sexy furniture, but one thing you could do is load it up with software from its time and just retro compute for fun. I’ve seen people do that to play old windows 95 games and stuff.

Put the cheapest, crappiest Windows PC in it and post it on some Mac forums.

Heat a room.

You really need two for a decent coffee table, so no ;-)

Around 15 years ago when my college was decommissioning them we used them as doorstops in the IT department.

If you like Amiga Workbench, you can always try MorphOS. But that is not a straightforward process to get into. And it's not free software...

If it's an earlier model, they make great 'retro' games and software machines. Install 10.4 Tiger, set up the Classic (OS 9 environment). That gives you a decent chance of running stuff from System 6-ish (late 80s) up to mid 2000s. Not like Macs had a lot of games or unique software, but it can be cool for the heck of it.

Also, with their FireWire ports, it can be handy if you still have old DV or HDV camcorders, pretty straightforward to capture old tapes. The later models are better for this purpose, more processing power and better graphics cards.

If neither of those use cases appeals to you or sounds like an applicable use case, the G5 towers are the best to use for ATX case mods. But you did mention you didn't see a point in that. Therefore... Recycle it or pass it on to someone who is interested in tinkering with it. After 20 years, just like a lot of computers from that era, they don't have alot of justified use cases... And that's okay!

We used a G4 as a doorstop for a computer lab, could bring ourselves to throw out that 1 ton beauty

Hold down a decent pile of paper? Block a door from squeaking open when the house settles in the night? Keep a cat from rolling down a gentle hill? Make a child cry when they unwrap it some holiday morning?

Dude! I saw this cool thing one time where they made a bench out of two of those. It was just a flat piece of wood that connected the two towers (lol)

Never have too many cheese graters

Install Mac OS 9 and play Yoot's Tower

Can you remove the innards and put something current in it?

Or is it built in a way that it's forever useless?

Hold down a lot of papers.

If you don't install some new smaller hardware in it, make art of it, throwing it off a building (just kidding, don't do that) or painting it in cool colours or why not make it a jukebox!

It might be kind of ironic to put a raptor computing mobo in it.

I own a G4 power Mac are they valuable ?

I had either debian or Ubuntu on an old ppc Mac laptop around 2007/2008. Worked well. Doubt there is much currently going on in the dev community though.

I have one I took from work when it was going to be disposed of. It should still have a working copy of Final Cut Pro 7. I still haven’t tried turning it on and I’ve probably had it for 9 years now. Any good old software on it?

I am not familiar with this device but everyone seems pissed at it why ?

send it back to apple. what waste of resources for some contemporay bs.