When starting from scratch: yes. When maintaining a mature application: no, because then you need to keep in sync the app and balsamiq and there is neither the time nor the will for that. And the money.

I'm still designing on paper with crayons (not a joke)

I design with pencils, but I thought crayons would give the PM something to chew on when there is technical discussion.

Are your designs huge ?

One screen per paper I print with special guides. So, I've got various resolution represented. The I just take pictures of the drawings, load them into this webtool and connect them together.

Like a super low budget Balsamiq

I'm kinda digging the idea.

Maybe I'll show HN, it's one of those ideas I have that just feels "too dumb" to be useful outside of my universe.