Is it worthwhile to learn French?
Of course, it is worthwhile.
Here are some reasons:
Because you are eager to learn a new language
Because French is the most practical foreign language which is spoken in more countries than you thought (Canada, Belgium, Switzerland, more than half of African countries,....) , and which is one of the two official languages (with English) at the UN, UNESCO and at the Olympic Games.
Because it could be a real asset in your professional career
Because you'll be able to deeply discover a rich culture.
Because French is a creative language. French literature is recognized worldwide, we have some fantastic author such as Victor Hugo, Alexandre Dumas, Albert Camus and so many more. It'd be a chance to be able to read their texts in their original language.
Because French is also a door to learn other languages. Learning French helps to learn other languages, including Latin languages (Spanish, Italian, Portuguese and Romanian).
Because French is not such a tough language to learn for an English speaker. Actually, 50% of English words come from French.
I'm answering this question from the perspective of someone whose first language is English.
French is reasonably similar to English:
1.The language of the ruling class of England was French for a long while, because the ruling class of England was French.
2.Both are, in part, descended from Latin
3.France and England are culturally reasonably similar.
French is different from English:
1.The syntax is different, you can't just learn "words" and string them together to speak French
2.The way in which verbs conjugate and nouns decline isn't really a concept you come across in English.
Put the two together, and you have a language that is reasonable easy to learn, but different enough to force you to learn different "patterns", and you end up with a way to think about linguistics through a practical example, rather than abstractly... ... and more broadly, you learn how to think in different ways, which is a very, very useful skill.
So, yes, I'm glad I studied French as a child, and certainly glad that I took advantage of some lessons in my 30s when I worked for an Anglo-French group.
... but for me, the utilitarian benefits are outweighed by the "mental workout" I get thinking in a different language.