Some languages bundle all of their dependencies so you can be relatively sure they will run the same on prod. For others (Python, Ruby) that use many system libraries, containers may add value
Yes, which is where you can reach for firecracker for example. But docker gets you 95% there. If kernel makes a difference you can make the decision about the other 5%.
> Some languages bundle all of their dependencies so you can be relatively sure they will run the same on prod.
As long as they're static, vendored dependencies. Otherwise you're still likely to run into pulling something very common like openssl, zlib or libuv from the system.