The term "virtualization" is being used in this context to mean using features of the hardware to build virtual machines that run at native performance on computational tasks. In contrast, the app you linked to is just relying on JIT compilation to emulate the guest CPUs.
It is not even relying on JIT, because that’s not allowed unless you are a browser engine and in the EU.
AFAIK, the version in the app store has poor performance compared to the "sideloaded" version. This is due to Apple rules.