The major practical difference to the average American citizen, is that the FDA is a federal organization, and so must still follow the federal ruleset when licensing drugs, even for products that will only be sold within a given state.

If an Oregon pharmaceutical company wanted to try to put THC in a pill; do a study for its positive effects against, say, anxiety; and then get it bottled and sold at drug stores—they still wouldn't be able to, because, even if the government of Oregon would love for them to do so, the Oregon state legislature isn't responsible for allowing or disallowing that to happen.

Whereas, if a Canadian pharmaceutical company now wants to attempt to get a cannabis byproduct licensed for prescription or OTC usage in Canada, they now totally can.