Perlis epigram 19: "A language that doesn't affect the way you think about programming, is not worth knowing."He maintained that it transformed one's way of thinking about a problem.
With APL you do go into it wondering whether the effects will be reversible...
Calculating pi is a much more virtuous exercise than mining crypto, say, but heat pumps will still win by dint of pulling in heat from the outside air (even if it's quite cold). The computer is merely 100% efficient at taking electricity and giving you heat; an electric heat pump will do much better.If you are going to heat your house with electricity anyway then the computing power is effectively free.
Was this advantage a primary motivation for a lot of users, or just a side-effect? Iverson's Turing award lecture Notation as a Tool of Thought certainly presents the compactness as a design feature.I always thought APL's major advantage was the very condensed source code which only lasted until systems could afford enough RAM to use more conversational syntax.