Updating BIOS is a very common practice. To advise against it, is not a smart idea.
It fixes issues, add more compatibility for newer devices and can resolve optimization issues, just like drivers would for anything else. The "dont change it if it isn't broken" tactics is what ill informed techs use to get out of doing something properly.
Nowadays it is hard to brick your BIOS doing an update. As long as you follow the manufactures recommendations and download the exact BIOS version for your board. You shouldn't run into any issues.
And in the case you do, you always have hard BIOS reset (removal of CMOS battery) as a last resort if that was to ever happen. Which is very unlikely if you followed the proper manufacture instructions.