It seems to be purely cosmetic, judging by the bits that have peeled off and not caused the bars to instantly fail! And the woven top layer of CF is part of the cosmetic appeal, from what I’ve learned about the stuff. I have other Easton CF bars with no obvious lacquer on them.
It does serve a purpose, but you can always replace it. It’s a fairly regular job to have to do on sailboats, sand the mast down qith 180grit and a lot of water until you hit the fibres, then coat it with a good quality varnish. Note, this won’t be something you get from B&Q you’d need to go to a decent dinghy/yacht chandlers, and the durability is proportional to the effort, spray on varnishes aren’t particularly durable, the 1-pack varnishes last about 2 years on a boat, and the two-pack 4+ years, but are a PITA to sand off again.
BUT! Most of the damage on boats comes from sunlight degrading the lacquer. Unless the bars have been left outside in the sunshine and never ridden off road, I’d presume that if the bars are old enough to look that tatty that they’re due for replacement.
And after all that, buying new bars will be cheaper. If you just want to spruce them up then 240grit to key the surface, wipe clean with IPA and a rattle can of paint from Halfords should give OK results for <£10.