I think you are right that optimising engineering cost is the goal of these practices, but I believe it is a bad thing.
Nowadays we have the most powerful hardware we ever had, yet everything is slow. Sure we reduce dev cost, but the end user is paying the price difference with its time in my opinion.
In the end the only people that benefit from this are the owners of the product, making more money selling unoptimised software, devs maybe get a bit more money, but probably not that much.