I would say it’s mostly essential here. There are some places where growers get by without planting on top of terraces. I know one peach/apple grower who didn’t do any raised plantings, but he is on top of a nice hill, and the ground drains well, and doesn’t have any seeps where he planted.
Growers up by the MO river don’t plant on raised plantings. That ground generally has good slope and lighter soil (I think it has more sand.)
I probably have the tallest terraces for a peach planting that I’ve seen. Most people don’t push them up that high (they were actually higher when I originally pushed them up, but they’ve settled.)
Making them that tall has it’s pluses and minuses. The taller terraces have steeper sides, so it makes picking harder. And it’s a real pain for my 50+ body to walk across, going up one side and down the other on each terrace, to get across the orchard (sort of like going for a rigorous hike). It’s not bad to do it once in a while, but if you do it several times a day, it gets old. Sometimes, if I’m in the middle of the drive lane, I just walk to the end, if I need to walk across the orchard, so I don’t have to walk up and down the sides of the terraces, but that involves wasted steps.
On the plus side, I think the trees have definitely benefited from being a little higher off the orchard floor. I’ve seen trees on the lower part of the orchard more damaged from frost, when the upper part got no damage, so I think the extra few feet helps some against cold air settling.
Another plus is that the branches which hang over the terraces toward the drive lane are less apt to touch the ground if they are heavy with fruit because the ground is a little further away.