I think the UI should explain what it is. You can't give too much information for something like this.
As it exists, it looks like a programmer added it last minute as a utility that only they understood what it does and when to use it. How would this pass user acceptance testing?
Why not make some simple changes:
The label on the button is too vague. With many different firmwares involved in a ecosystem like Hubitat, what does it to? Pressing the button to figure it out is non ideal.
A little paragraph explaining what it is in the popup window would help. Showing the current version of the zwave radio firmware with time/dates, etc.
Further details explaining why you'd want to update the firmware or not.
A link to the support page for all this would help as well.
Or.... Remove the button, automatically update firmware (which I actually think it does already on today's firmware version - might not in the future though?), and avoid all that work completely.
If I remember right the firmware updates used to always be manual (I think there has only been 1). But then some people's radio would get busy and not perform the manual firmware update, so they added a check at boot that upgrades it automatically during boot, thus making the button useless (today).
But yes, if they keep the button it may be good to add more description to it's function.
There is (or was at least, haven't checked in 6+ months) a hidden url to see the firmware version. It is hidden because this is a consumer hub, and they aren't supposed to worry about junk like that (I assume).
SmartThings is more "consumer" than Hubitat, and it has lots of details viewable, although it is on the IDE which only power users would generally use. Still, having more information (and not on super secret pages) usually helps, not hurts customers.
Here's my argument. I would put the firmware version as a viewable detail before I would put a button that is confusing. The support emails have gotta be 3x as likely for the button. "What does this do?" "Why do I need to press it?" "When I press it it says there is nothing that needs updated but I want to update the firmware on my Inovelli Dimmer!" etc.