Historically, it’s a strange question to ask. Before the emergence of widespread plastics, trees and shrubs were almost exclusively dug and moved during their dormancy. Because of the enormous weight of the soil surrounding roots, it makes sense to just shake it off and move the plant. It is the most energetically efficient way to plant.
There also happens to be huge benefits to growing trees and shrubs in-ground, instead of plastic pots. Imagine you wore high heels daily and never took your shoes off—do you think the bone structure of your feet would be healthy after a year? Trees grown in-ground have a healthier root structure, with roots pointing outwards like spokes on a wheel, not bound up in circles, pointing inward. You can grow and sell trees and shrubs in pots (and we do), but they are almost always inferior to bareroot, and for a higher of cost of production.
When it comes to planting, the expert advice is to plant directly into native soil without amending. Amendments, such as compost and mulch, go on the surface. This allows the roots to grow into their environment freely. When a potted tree or shrub is planted, there is now a bright line between the existing potting soil and the new native soil. This can be confusing to the plant as well as the grower during the transition, as the potting soil dries out at a different rate than the native soil. Bareroot plants go directly into native soil. Now you are free to use your senses--check the soil with your finger, is it starting to feel dry? Add water. Is it plenty moist? You can be confident those roots are not dry.