[ken]

The numerical tower is one of the features of Lisp that the Algol descendants have not yet stolen, and I don’t know why not.

“Efficiency” is tough to believe given all the other inefficient yet nice features that have been universally adopted, like Unicode, variable length lists, bigints, etc. In many dynamic languages, every method call is a hash table lookup, yet we’re expected to believe they don’t use Decimals by default because it would be too slow? In C++ I’d buy that excuse.