I do not think the internet and youtube is the end all be all nor measure of a computers worth.Speaking as someone who does trust Windows with their files, and generally lives in Windows, you can get fairly recent versions of Windows running on rather ancient hardware. And because of that, you have a library of software open to you on a computer 20 years old that would just be impossible on a Mac.
The Pentium 4 doesn't quite line up to anything PowerPC, though they were released around the same time the PowerPC G4 came out. But as slow as they are today, you have to consider the fact that the vast majority of Windows software can still be run on them. All one needs to do is run Windows 7, and you've got something like 90-95% support, still.
Linux has its own issues, as 32-support has been dropped from mainline support on the major distros. But there are still plenty that support it, and in current versions, too, from what I've been able to dig up. It does look like, if it's not already been cut, support for it is on the chopping block, though, depending on the distro.
But that comes down to community support, as most Linux things do.
If "getting on the internet" is the number one test of if a computer is worth using, and I personally don't think it is, those old 32-bit systems aren't in that much of a better place than our old Macs, but they'll likely have access and development for years to come.
If only because Windows doesn't change much, and backporting forks of Firefox to XP is apparently not nearly as hard as it is for anything else.
This test was to see how well a similarly spec’d PC with a modern (or 90-95% support like you said) faired against a PPC Mac.
I actually set up a PC for XP awhile ago, it’s a 3.06Ghz Core2Duo and it was actually a Windows 7 PC. I did it to play a couple games that don’t work on anything above XP (Rise and Fall in particular)
It was extremely easy getting XP on the web, and I found many browsers still working for XP. By comparison it is insane as XP came out around the same time as Mac OS X 10.1 Puma.
Little known to this forum, when I was in middle school up to my junior year I had two main computers, an iBook G3 500Mhz, and an IBM ThinkPad A22m which was an 800Mhz Pentium 3. I got an iBook G4 around 9th grade though. Prior to the G4, I ran that ThinkPad with Windows Vista, and then 7 when it came out.