Title is misleading: no company has made any deal with any union. This is legislation to reduce insurance coverage in exchange for limited rights to unionize.
This is per-sector negotiation, affecting all rideshare companies, with qualified unions (that seem to only include SEIU) over wages, leaves, dismissals, and health insurance but not fares, that reduces uninsured insurance coverage from $1M to 300K (thus shifting the burden to drivers and passsengers).
Uber sought the deal after recent court rulings showed prop 22 (costing $100M's) wasn't the complete bar they'd hoped against the unions. SEIU may have gotten the deal in exchange for supporting prop 50 (redistricting to counter Texas). Governor Newsom is eager to play middleman-advocate for both business and labor.
This wouldn't have happened before Waymo's demonstrable successes.
But... I wouldn't want to be an outlier i.e. serious injuries. That would require suing the driver that has few/no assets.
Uber/Lyft sure as hell ain't going to let you sue them for a dime.
What did the insurance cover? (Also, were AV insurance standards also reduced for Uber and Lyft?)