Legality is only one factor I consider in whether or not I will use a drug. It makes drugs I might be interested in more expensive and difficult to obtain.
I don't use cannabis because I dislike it intensely. I consider the effects unpleasant and would not use it even if I could get it for free and needn't consider the legal hassles it would introduce into my life. (Almost no risk from police, but it would jeopardize nearly any job I might have.)
There are a handful of psychedelics that I would use regardless of their legality. The only obstacles are accessibility and price, and the fact that I am currently abstaining.
I am avoiding almost all psychoactives right now, except for caffeine and nicotine, because I am struggling to get my psychiatric medicine adjusted to where I am behaving like a functional adult in society. I don't want to interfere with the medicines I require.