In the general case, no, but there are some rare specific cases where that does work.
If you’re trying to produce Linux media that will boot on a single-board computer that has an onboard bootloader, like a Pi 4, you can indeed just partition the target medium and copy the files manually (been there, done that, working with a custom Gentoo install with no ISO).
If the bootloader has to be on the target medium (as it would for a desktop or laptop), then that won’t work unless you also do a manual bootloader install after copying everything. Not impossible, but at that point you’re hitting the level of complexity where it’s easier to figure out the correct dd command.
(As for Windows? Don’t even bother. It hates being worked on with anything but its own tools.)