A basic networking question from a student

Hey r/networking

I'm currently completing a degree in engineering/computer science, did a subject on basic networking and encountered a rather abrasive Lecturer.

I'm a student so i apologise if some/all of what I say doesn't make sense.
The crux of the issue I had came in the form of a practical involving a Cisco router and 4 switches. The goal was to setup a basic network, cabling, loopback, 4 VLANs on each switch etc. My setup passed scrutiny bar 1 (possible large?) oversight. I didn't hard code one VLAN to be the root bridge for a specific switch. Because of this, I received a penalty of 50/100, failing the assessment and ended up failing the unit.

I've been told by the faculty that this is a major error in a network. The reason given is that if the setup from this switch was copied to a new one (if it blows up/needs replacing) the hexadecimal value it holds might be higher/lower meaning the firmware might designate a previous switch in the network, as the root bridge for the VLAN in question.

I suppose my question is: Is this as big an issue as it's being made out to be? I have an IoT major and don't plan on getting a job in networking, so I'm willing to cop this decision but it seems extreme. Especially since it was an introductory unit.

Any advice is appreciated.