QEMU

Which is a better way to install and use QEMU? The answer probably depends on the use case, In my case I just want to use QEMU for two things: 1) trying/testing OS, and 2) isolating browser usage (e.g. for necessary services I don't trust).

I have come accross these two advice for installation:
sudo apt-get install qemu-kvm qemu virt-manager virt-viewer libvirt-bin(https://www.unixmen.com/how-to-install-and-configure-qemu-in-ubuntu/)

sudo apt install qemu(https://www.poftut.com/qemu-tutorial/)

The latter seems of course much simpler, but why the difference in number of packages to install? Are the extra packages only necessary for special purposes or what?

advice will be appreciated