I used it as an installed desktop environment at a workbench in a non security context for a year. It was a pain in the butt in like a million ways.

Even when I used the tools kali ships with regularly I either dual booted or ran it inside a vm.

If you wanna understand why every time someone asks about using kali as a daily driver even on their own forums, a bunch of people pop up and say it’s a bad idea, give it a shot sometime.

You can just install the tools you want on your host OS. But if it's like hundreds of tools then yeah makes more sense to run it inside a VM, just so it's all nice and separate from your daily-driver. And you may think it's funny but the performance of Linux-on-Linux is actually pretty good, and there isn't much of a RAM/CPU overhead either. And if you're really strapped for RAM, you could use KSM (kernel samepage merging) and ballooning.

Many Linux users use VMs (or containers) for separate workloads, and it's a completely normal thing to do. For instance, on my homelab box, my host OS is my daily-driver, but all my lab stuff (Kubernetes, Ansible etc) all run under VMs. The performance is so good that you won't even notice/care that it's running on a VM. This is all thanks to the Linux/KVM/QEMU/libvirt stack, if it were something else like VMWare or VBox, it'd be a lot more clunkier and you can feel that it's running on a VM - but that's not the case with KVM.