My website mainly targets international users, and I know most people in international countries know English. However, I try to put myself in their shoes, for example, if I lived in Spain I think I would prefer to read Spanish websites over English ones so; this is why I'm thinking adding localization to my website would be a good feature to include for future growth.
You are 100% correct. Just like you, customers in other countries want to understand what they're buying. Studies have shown they're actually 6 times more likely to buy when a website is available in their native language, and that 85% of global shoppers will not buy at all in a non-native language. Having a translated website also helps people find you/improves your SEO, as even if someone is willing to check out a site in English, they search in their own language.
I'm happy to help further. Just let me know, and thank you!