I notice among people I talk to more enthusiasm toward learning French than Spanish. This confuses me; my feeling is that Spanish unlocks far more countries and speakers than French does and so is a more natural first choice.

What do people think motivates this choice?

Spanish and Portuguese both have that global appeal, I think French probably also will with the rise of Africa

Possible, though I don't think any of the most rapidly rising African countries are francophone, and also things like this are happening:

Devil’s advocate in crypto. Previously @rainbow. Global head of Macro at West Ham Capital

Yeah they aren’t, Francophone Africa is big but I think smaller than even the population of Brazil. Def not the same kind of global language as Spanish . Actually considering these things as we contemplate moving with our kids to Europe. Spanish, Mandarin, Portuguese probably better bets to learn than French

Also if you learn Spanish you can mostly read French 90%

Possible, though I don't think any of the most rapidly rising African countries are francophone, and also things like this are happening:

https://www.universityworldnews.com/post-mobile.php?story=2023070814210465

https://www.africanews.com/2023/07/26/mali-drops-french-as-official-language/

This was one of my considerations when wanting to get fluent in French (many years ago).
Recently I've been wanting to learn Spanish, basically for the more countries unlocked reason.