For weed control and moisture retention. Any harm in using for vegetable garden?

I tried it and it resulted in a population explosion of slugs for me.

Other than the slugs, pill bugs and stuff that lives under it, no.

Coming up my neighbor blanketed his garden in newspaper. Kept the weeds to a minimum.

But where would you find that much newspaper these days.

Using it under mulch for years.
Before that I had slugs and cut worms.
Better drainage and beer traps cured them.
Chickens or fowl make them gone too.
Nobody likes pulling weeds, me too.

I like to take a section of new paper rip it on the fold to the half way point , put it around a tomato plant repeat coming in from the other direction , so that the rips don't line up for maximum weed protection , stab tomato cage down through to hold it in place and water

Use cardboard here no problems

I use cardboard with wood chips over it , you can't even find it by the next spring

my son brings home pallet size sheets and my neighbors brings me large boxes from his work when he gets them I could use a pallet of pallet size sheets each year

I have used paper and cardboard with straw on top. And by spring it's gone. Then I till it all...

I have done this for close to 20 years , works great

Preen