Vaccines do reduce transmission, via (a) reducing the chance of becoming infected in the first place and (b) reducing the average duration of the infectious period. As far as anyone can tell, this holds up for omicron, at least for boosted individuals, though it's certainly less effective at preventing infection.
Some Covid vaccines reduce transmission. And it keeps you out of the hospital, which for a human-to-human transmissible disease like Covid (and unlike Lyme’s), is a big deal.
