Yep, a whole ton of those machines went to the landfill. That specific model was subject to a class action lawsuit against Dell that cost them over a billion dollars in the mid to late 2000s over using fake Nichicon capacitors that exploded or leaked after less than a year of use. I'm very surprised that machine still works, because the replacement motherboards and power supplies used the same fake Nichicon capacitors and failed again within a year.
Between 2006-2008, I replaced thousands of Dell motherboards and power supplies in GX280 and similar machines Dell released. I was regularly recapping boards and PSUs from that era of Dell up until probably 2013 or so. Still occasionally get those machines in to be recapped.
If you need a fast Pentium 4 machine, I guess it would work for that, but I'd recap the entire machine, including the power supply, before using it in any serious capacity. The power supply is especially important to recap, if some specific caps fail, it can take out other components inside the power supply and make the repair much more difficult. And while it is a bog standard ATX supply, the pigtail is super long for wire routing, and a normal ATX supply will have trouble reaching the lower drive bays.