It's probably there for DO's sake. SSDs have limited rewrite cycles, and each secure wipe will definitely shorten the lifespan of the drive much more than a simple quick wipe. This translates into cost savings.
It's called a dark pattern.
I could argue that it benefits the customer as well.
If it costs DO more (because of disk wearout) then in theory they would have to raise prices in order pay for their higher costs. And those higher costs could then disrupt the balance in pricing that makes them attractive.
My point is that forgetting the numbers you can't say it only benefits them. Being able to offer lower prices (because your expenses are lower) also benefits the customer as well.