With the way linux is used these days, I'd guess the number of systems with untrusted local users is pretty limited. Even with shared hosting, you generally have root in your VM or container anyway. Unless this enables an escape from that?
Still the risk that people who run "curl | bash" without care could get bitten, but usually its "curl | sudo bash" anyway...
Lots of shared hosters don't use VMs or containers. It's some arbitrary number of people logging in to a shared system, each one with a home directory under /home/THE_USER_NAME. i've had several such hosters over the years (thankfully not right now, though).
So containers don't protect you, only a VM.
How so?
Things like HPC clusters are multiuser & don't entirely trust their users. If they did we wouldn't need users/groups/permissions etc in the first place.
And then there are users running claude-cli and friends who may just find it convenient to use a local root exploit to remove obstacles.