But will they be instituting the necessary inspection and testing to assure patients that the 'oil extracts' they're inhaling or eating are what they claim to be?
With raw herbal material, verifying the plant's identity is easy enough - you can see it, smell it, and taste it, and one or two hits are sufficient to verify potency and variety.
Marijuana is a complex herb. Its two primary cannabinoids, THC and CBD, are the prime components of the 'high' - THC gets you high and provides some of the medical effects, while CBD - not psychogenic on its own - alters the THC high, and provides even more of the medical effects
The plant contains many other cannabinoids and terpenes that may have medical benefits (but are very poorly studied, since they don't get anyone high), and all the constituents combined seem to create a "cohort effect" that produces synergistic effects not seen with individual components.
"Oil-based extracts" may have highly variable THC concentrations, highly variable THC/CBD ratios (and, indeed, may have no CBD at all!), may contain some or none of the other cannabinoids and terpenes, and may contain large amounts of CBN, a breakdown product that reduces the THC high and causes sedative effects.
Additionally, extracts may contain impurities from the extraction solvent (heavy metals and long-chain hydrocarbons), residual solvent, and other unknown contaminants.
And of course, they could contain one or more of the synthetic THC-analog cannabinoids that underground chemists have been playing with - some of them many times the psychogenic potency of THC, but with different effects and side effects, and with no centuries-long long record of safety and effectiveness.
Turning a longtime multi-substance herbal recreational drug into concentrated, refined, single- (or limited-) ingredient extracts, or modified or synthetic analogs, is a path fraught with danger - look at coca leaves vs. cocaine, morphine and heroin vs. opium, or even wine and beer vs. gin (see Hogarth, et al.).
Oil of Wintergreen is a candy flavoring, a useful medicament, or a deadly poison, depending on dosage and route of administration.
Marinol (synthetic single-ingredient oral THC capsules available by prescription for certain severe conditions) is less effective AND has far worse side effects than smoked herb. Ask the cancer-patient community in a medical-MJ state. They'll tell you.
Add the danger of contamination, the substitution of potentially hazardous, untested synthetic analogues, and all the other possibilities of inhaling vaporized extract of "Trust Me", and the elimination of the consumer's first line of defense - the ability to examine the raw material - begins to look less advisable than its proponents might think.
They're trading the dangers of smoking a natural herb for the dangers of inhaling or eating unknown, untested, unverifiable chemicals.
Personally, I know which one I'd rather risk.