but I fail to see where this fails as a domain
First consider the market as it is today.
This is still an emerging market in early days.
The consider how many other, better domains are out there like this.
Think about some of the other types of names that will sell before mart like -
store
shop
etc.
Then understand that there are many terms to replace Marijuana -
weed
pot
ganja
mj
etc.
There are too many better, more appealing combinations for end users to choose from.
There are 3 terms in this name also ( Marijuana Mart Ca ), another mark against it.
Other, better and shorter versions will sell before this one.
What about the other choices a business could choose like
Marijuana store Ca
Marijuana shop Ca
Marijuana universe Ca
Marijuana planet Ca
Marijuana direct Ca
etc...etc...etc !!
When picking or bidding on a name you have to look at the uniqueness of the name as well as the other alternatives available to the end user.
Think about what other, cheaper choices an end user has without paying you $$$$$$.
Also, if this is targeting Canada, a dot ca would make more sense, and this adds another mark against it.
If it is targeting California why would ca be necessary at the end if it was a local shop?
If it is not local they could use - Marijuana Mart Calif or any number of other names including the name of the city they are located in.
If they wanted to do business outside of Canada or California they would not use ca in the name and would use a more generic name instead.
It really comes down to how many other choices an end user has, and with this name and the still young market, the only way you will ever sell it is if someone, down the road, names their business this exact name.
And that is a long shot and a long wait, renewing a name that will probably not sell.
This is the main reason one word dictionary names are so valuable - because there are few, if any, better alternatives to choose from.