It's more that any consumer grade processor seems to have this limitation.

I have an i7-6700HQ for example, and I can either have Hyper-V turned on (I'm on Windows) in which case I can only run 32-bit VM's with VirtualBox, or I can turn off Hyper-V in which case I can run one 64-bit VM on VirtualBox, and then only 32-bit VM's past that.

If I'm doing Android development, I can't run a 64-bit VM at the same time as the Android emulator is 64-bit.

Sometimes I want to run my web server, an Android VM, and maybe a Redis server on Ubuntu in a VM. I can't emulate Android and run a 64-bit VM, so the 32-bit Ubuntu distro is invaluable here.