Both should have the same effect: the /dev/loop-control devices should become available. systemd-tmpfiles-setup-dev.service creates the device node "dry" based on modalias data, while modprobe@loop.service creates it fully, because the module backing it is loaded properly. This should shorten the deps chain a bit, simplify things and allows us to focus on the stuff we actually need (i.e. the loopback infra) instead of all entrypoints anyone might possibly need (i.e. the device nodes)
System and Service Manager
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