The difference is that unlike building your own expensive and potentially dangerous liquor still, a personal supply of cannabis can just be grown in a sunny plot of land, or if you want to get real fancy, with indoor growing equipment that also has "legitimate" uses. It is a weed, after all.
Which also takes time, energy and depending on how much you grow, a possibly higher energy bill at the end of the month.
I know for years, cops used to co-ordinate with the local energy companies to spot houses that were suddenly spiking with energy usage and tip off the cops.
This ran into issues of guys trying to tap into their neighbors HVAC system or AC system to get more power and stay off the energy companies list. I would go out on a limb and say doing stuff like that is just as dangerous as having an illegal still.
