The kind of task is not the same. With a calculator, you are delegating a very specific, bounded, and well-defined task. Being unable to approximate non-integer square roots by hand isn't the same as not knowing what square roots mean or when they are applicable. However with LLMs, people are often (trying to) delegate their executive-function and planning.
Another way to tell that the tasks are qualitatively different is to look at what levels/kinds of errors users will tolerate. A company selling calculators that gave subtly but undeniably-wrong answers 5% of the time would rightfully go bankrupt.
If you want to compare LLMs to something of yesteryear, it's closer to hiring someone to do the work for you: That's always been considered cheating, regardless of how cheaply the accomplice works or how badly they screw up.