Building from source can take hours or even days on low-end machines though, unless you can get binaries for the apps you need for your old CPUs.
Both support binary third party packages.
But building on Linux will also take just as long, so really a non-issue :)
I did install pkgsrc on Ubuntu to get around snap but building anything took such a long time even on modern hardware. But that was building all the dependencies from scratch. After that it should take less time.