i think it's better because as a people it's better to have no negative stigma surrounding it at all. decriminalization would mean they are basically still saying it's bad but just lessening the punishments. as long as you could grow it yourself is all that matters.
because its legal... you can flock it anywhere/grow it/whatever.. decriminalized means. you cant get in trouble for smoking it but its not legal to sell.
Legalizing is better because this is something that should have never been made illegal in the first place.