Secondly, you only rarely need to because everything you use is in the package management system, thus compiled for the platform you are on (and against the same versions of the libs as everything else, thus only one, up to date, version of each lib and only the libs you need).
The only reason I've sometimes do qemu-system-arm and chroots is I'm a software developer often working on ARM Linux (from x86 Linux).
Third, I will also point you to:
But normally, you use a pure system. All 32bit, all 64bit or all ARM, etc etc. Closed crap can muddy your system, for instance requiring (normally old) versions of 32bit libs on a 64 bit system, but the solution to that is to not use closed crap.