For sure, but most PowerPC hardware now, especially G4 and older, isn't going to be a very good experience on most hardware. The glory days of PowerPC Linux were the late 90's to about 2013. Especially with Debian. But someone that just wants to appreciate an old Mac from time to time isn't really going to get that experience with Linux, unless they have a deep bag of tricks. People without those skills will have a never ending string of roadblocks.
But Tiger can run well on even a G3.
BSD is what someone who wants an open source OS on Mac PowerPC should be using in 2020 IMO, but that has an even higher learning curve than Linux.
This is why I don't run Linux on my Macs. I love Linux, but I have a collection of PPC Macs because I like them. I can run Linux on literally anything. In fact, openSUSE is installed on my ThinkPad right now and I use that if I'm not on my 15" PBG4.
Not to say I wouldn't be insterested in trying PPC Linux; I've used it before (if anyone is wondering, Ubuntu 16.04 does
not run very well on a 400Mhz G3). I like older Mac OS X, and I like the PowerPC platform. So Tiger or Leopard is just a natural choice for me. In contrast, I despise most versions of Windows, especially 10. So PC's get Linux installed.
I have also been slowly getting into BSD, but not on PPC (well, sorta being as Mac OS X
is BSD). I have a pfSense box and a FreeNAS box set up. Though obviously not desktop operating systems, they're still FreeBSD; and doing anything outside the book requires some learning curve.
This thinking that Linux is always lighter and faster is rarely true anymore.
In my opinion it's never been true. It can be, but rarely out of the box. Maybe if you used a distro like DSL.
Linux has always been pretty slow out of the box for me on most systems, and using a DE that has a lot of modern enhancements and eye-candy like KDE will eat up as much ram if not more than just running Windows.
Back in the day I had a Dell Optiplex with a later Penitum II of some vintage. Ubuntu (I wanna say version 6 or 7?) was not any faster than running Windows XP on it. Both were equally as mind numbing.