APL is an interactive language returning answers immediately.
Yeah, right... Ever sat over 'Bello Gallico' trying to figure out what Caesar meant with that gibberish? I can tell you, there's no way of an immediate answer...

APL is easy to learn and use;
Yeah, Latin and easy to learn... Right... Use? Well, my teacher could speak Latin more or less fluently, but he's about the only one I know personally...

if you make a mistake, it is easy to fix.
Hmmm, like binding the adjective to the wrong noun in your translation, realizing a dozen sentences later that somehow the story doesn't make any sense?

Oh, wait... You are talking obsoleteness here, aren't you? *looks most innocently*
In that case: Latin has its uses... It helps very much in learning other languages that originated from it (like most european ones) and in understanding those you haven't learned yet... Besides, it makes you look educated when you occasionally let one of those latin proverbs slip into your conversation or use latin termini wherever possible. As is said in latin "quidquid latine dictum sit altum viditur"...