As I understand the landscape here, the big enabling win of microvms is faster boot time; there's a cool qemu-lite slide deck that goes into detail about how they cut down boot time:
We use AWS's Firecracker to turn our customers Docker containers into Firecracker microvms (Firecracker is Amazon's Rust VMM, the engine for Fargate and Lambda). Anecdotally: in my dev environment, the difference between Firecracker boot times and native Docker container startup is imperceptible; the logging we do swamps the VM boot stuff. It's very fast.
https://www.linux-kvm.org/images/d/d2/03x05B-Chao_Peng-Light...
The big win was slashing away the BIOS stuff.
We use AWS's Firecracker to turn our customers Docker containers into Firecracker microvms (Firecracker is Amazon's Rust VMM, the engine for Fargate and Lambda). Anecdotally: in my dev environment, the difference between Firecracker boot times and native Docker container startup is imperceptible; the logging we do swamps the VM boot stuff. It's very fast.