Most creators don't treat it that way.
One thing I come across a lot is channels where the banner is either blank or it's something that was thrown up at the start and never revisited.
I did the same thing for a while. But every time someone lands on your channel page, that banner is doing a job whether you've thought about it or not.
The simplest way I can put it is this. Think about glancing at a shop window for the first time. You've made a decision about whether to go in within a couple of seconds. Your banner works the same way.
If it's cluttered or doesn't say anything specific, most people move on.
The ones that work have a clear promise in them. Not just your channel name. Something that tells a visitor straight away what they're going to get and whether it's for them.
A creator I came across recently doubled their visitor-to-subscriber rate just by swapping out a generic banner for one with a focused message. Same videos, same thumbnails. That was the only thing that changed.
Once the message is right, it's worth checking how it actually shows up. On mobile, YouTube only shows the central strip of your banner.
If your key text is near the edges, most visitors on their phone never see it. Just pull your channel up on your phone and see what's visible.
What does yours look like right now on mobile?