Interesting perspective. I think it's a question of appropriately using a calculator. The way I see it is that a calculator is a tool. One should use an appropriate tool for the job. You wouldn't use a chainsaw to chop an onion, and theoretically you shouldn't need a calculator to solve 18-5.
That said, in my opinion if you know how to use a calculator and why you do it that way, it's a very good way to learn.