That is really what it boils down to, it is what one prefers, there are no technical reasons one method is best or better. So that is probably why the videos don't try to clarify on that.
Most people will say it is best to use 'sudo', instead of 'su -', and there are ways to access the system as root, even when there is no password available. If one digs through the posts on this forum , (search foo), there are some threads on that, and a couple where they had problems with "sudo" , not working, like I said, it can be handy to be able to just use "su - ", if and when for some reason "sudo" does not work.
When I started using Unix, "sudo" did not exist, later they started using it on OpenBsd, but it was deprecated when, "doas" was developed, Linux still uses "sudo". All though it (sudo) is still available for OpenBsd as well, guess that is kind of a different topic, though:
https://en.wikipedia.org/wiki/Sudo
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https://en.wikipedia.org/wiki/Su_(Unix)
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https://www.beyondtrust.com/blog/entry/unix-linux-privileged-management-should-you-sudo
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https://kb.iu.edu/d/amyi
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Many do argue that it is best to use 'sudo', this applies especially to systems with multi-administrators, me, I am the only one using this PC, it all depends on what one prefers.