This is a good question!!! I think I will continue, try hit 200 days. I have enjoyed the progress, and.. my end goal is character design and storyboarding, ei.. rough animation. I have a long way to go, as I am still doing reference studies from other artists and don't know much about anatomy or clothes or hair. I got a lot to learn still.
Concerning.. the daily practice, yeah.. I mean you do 3D daily, you got the practice there. But you are right, blindly doing things over and over doesn't make you better at it if at all - you really gotta think a bit to really improve.
I have to do more controlled studies.
I don't do 3d daily, it's more like once a week very intensely with fits and spurts during the week wherever I can fit it in x_x
Good luck getting to 200 days! Though I feel like you're right and more controlled studies might be more beneficial than maintaininng the streak XD Meanwhile I wouldn't know as I'm very project oriented and don't do a lot in the way of studies x_x