It's Ruby though, where Array has "size", "length", and "count", all of which are equivalent. The programmer chooses which one they prefer based on the context or their style or the phase of the moon.

Ruby inherits the Perl philosophy of "There's more than one way to do it". Compare with Python, and its "There should be one — and preferably only one — obvious way to do it."

It's true that it makes the compiler less elegant, but Ruby optimizes for the programmer at the expense of the compiler.