Denim (either dark or beat up) is sorta the default. Samurai, blue blue, etc... all pretty much style it that way. That, or some loose cargos. I personally feel that the best way to wear indigo is with more indigo. Some do it slim, some do it regular, some super baggy. Slim makes you look a bit more "modern" in a sorta Japan meets #menswear way in a good way. Regular makes you look more casual, more "hey, I'm just out here drinking my coffee and eating this croissant." Baggy is sorta a take on that fitted, tailored top and slouched bottom that Rick does, except, it's not fragile like Rick stuff. Tonal it up. The secret is that the texture is sufficiently different from denim that it does not look like you are wearing a suit, though, a Sashiko suit would be pretty great.
Just think of the thing as a structured cardigan. You are going to Starbucks or a better place? You can throw it on. Walking the dog (I don't have a dog, but I hear that people do that)? Throw it on. Picking up your kids from school? Throw it on. Going for drinks with friends? Throw it on. Gonna get in a fight in that bar and might need your cuffs to choke some fool out? Throw on this sashiko jacket!
fwiw, I will throw this jacket on to do three of the above five things.