I can get weak coffee most anywhere. Why would I go out and pay for it? Maybe it's a cultural thing?

a unintended consequence to poor translation is sometimes "colorful euphamisms"...

I suspect they are refering to Cafe Americano, but they may think that calling weak coffee American in English is a bad idea.

Their 'Weak coffee' might be very delicious.

Did you try a cup, Joi?

Yes, it's usually referred to as American coffee here in Japan. I once made the mistake of ordering a cup of "American coffee". What you want is "Blend coffee". That said, it's a misnomer. If you want to name weak coffee, name it "English coffee".