I'll agree with all the reasons stated above.
Also 8x10" was big enough for Weston. The images you see in books may be larger than the originals!
Contact printing removes the whole optical system of the enlarger with its lens and alignment issues.
It is easier to retouch a large negative, if you do that.
Many interesting classic lenses are available for 8x10" and larger, and while enlarging negatives made with them may enlarge their optical faults, they often look great when used as they were intended.
Large negatives also open up the possibility of trying alternative processes, which are only available as contact printing methods.