[LeonidasXIV]

That's exactly why you virtualize, so you don't just have a bunch of small Pis being mostly idle but less but more powerful machines running a lot of virtual istances that on their own are also mostly idle but you can put enough on to put enough load on the higher-powered machine to be worth it.

In a data center they should have enough instances that virtualizing makes sense from the perspective of power efficiency.

[selfhoster11]

Virtualisation means you can get noisy (or nosy: see Rowhammer) neighbors. VMs are fine, but there are valid reasons to prefer bare metal for hosting critical applications.

[KennyBlanken]

Nobody is hosting a "critical application" on a Raspberry Pi4 in some random-ass no-name colo.