Medical weed through doctors' prescriptions for things like pain relief from cancer most likely wouldn't affect the labor force. It's not like Timmy and Susie could saunter into a shop and buy weed for funsies unless the state opened sales to the general public. Given that they fought Sunday booze sales and craft/draft/tap beer for so long partly because of the evil brew, I doubt they'd just open weed sales to everyone.

Cultivation of medical-grade weed, packaging, running dispensaries ... approving medical weed probably would create more jobs than a lottery where ticket machines and scratchies are installed in stores already owned and managed by someone else. The biggest jobs likely to be created with a lottery would be with the supervisory commission board - high dollar, going to friends and buddies, and not much else.