I too wish to learn Spanish. The reason being I wish to work for more people speaking in that language. I have done some of the freelancing jobs for mostly native English speaking nations. But I wish to some day for the Spanish speaking nations too. I think remote work and the freelancing in that language would be opening more doors for me.
Only English, right now. I would want speak passively in spanish too because more employment opportunities would open up for me abroad, like a translator, tour guide, or a teacher for example. Speaking a second language can also benefit my communication skills if I ever decide to on holiday abroad to a spanish country.
I only know English. I thought about learning other English but to me really there's no point as I don't travel that much and where I do travel they speak English pretty well. Once in awhile though if I talk to someone that knows another language I will ask them sometimes how they say certain words in their language.