do worms help plants??

if i were to buy a couple things of night crawlers and put them in the soil that im going to transplant my outdoor plants to would it help?

dead ones make good fertlizer and I think live ones help keep the soil loose so the roots and water gets deeper

I wonder what worms eat for food hope its not the roots

worms eat fallen foliage so be sure to keep them happy by dropping some decaying grass or leaves in with them

i put 18 nightcrawlers in my 3 gallon pot when i harvested the plants to my amazement they were all alive....then again my soil had alot of compost in it for them to eat.