Yeah but why risk it?

This is like asking “Is it alright if I leave my garage door open while I’m at work today? It’s detached from the rest of the house and I just store junk in there I don’t care to lose.” Yeah, I mean it’s detached from the house and let’s even say for argument’s sake, you live in a gated community. The risk is very low of someone actually breaking in and getting your valuable stuff inside your home. But by doing this, you’ve kind of invited people to come take a closer look at your house too. Someone decided to see what’s in your garage and didn’t see anything, but hey, looks like a bathroom window on the side of the house is cracked a bit. Could easily slide into the main house and take a peak in there. I would’ve never seen this from the sidewalk/city street until I got into the open garage.

Best case of a bad situation is that something gets into your XP computer and infects it. You don’t do much with it, so trashing it isn’t the worst possible thing to fix this issue. Worst case of a bad situation is you’ve infected that computer and now an infection is checking out the rest of your network and other devices on it including stuff you didn’t think of or stuff you thought couldn’t reach the web. You blocked your smart TV from accessing the web but left it connected to the router so it is still discoverable on the private network. Or you have a cheap Temu camera you got a while back and forget is still active and it’s sitting on your network with really poor security, easily vulnerable to attack.

I guess if you have that much faith in your network and devices, go for it, but probably not a good idea if you want the best possible defense.

If you really need something off the web to that XP machine, better to find a way to get it there like on a separate VLAN.