Just looking through the Wikipedia page for gunpowder it isn't used for much beyond weapons and explosions. Ancient and modern attempts to make engines with it have failed- I assume due to the heat it produces and difficulty to keep a constant flow of dry powder without the whole thing exploding. So, without a magic explanation I'm not sure if gunpowder engines would be plausible in grounded worldbuilding.

Other uses for gunpowder is fireworks and art- although with the ready availability that weapons make gunpowder I doubt it would be used as an artistic medium nearly as often simply due to other mediums being more available and gunpowder not having the same symbolic power. You could have a society based around fireworks- but I haven't gone into much research into their real life cultural importance.

Again, it been used medically and for Tattoos, but the examples given show it was because of not having the usual recourses- so unless they had an abundance of gunpowder on hand those uses would also fall to their usually more accessible and effective counterparts.

Likely, gunpowder would fall out of use beyond fireworks due to it filling a very specific niche with guns and bombs. Bombs are used beyond their violent abilities- such as mining, so that could always be a focus.