We’ve had to pull a bunch of invasive plants out at Sugarloaf State Park (California) because people thought sprinkling “wildflower seed” packages around after the fires would be helpful. Hint: Cape Daisy seeds in natural areas are not, in fact, helpful.
Seed bombs in general are a very ineffective way of planting things, you’d be better off just dumping a seed packet out on the ground in most cases.
However, I’m all in favor of guerilla gardening in abandoned urban areas. Just make sure you’re not planting anything that’s going to be horribly noxious and invasive - it’s generally best to stick to whatever wildflowers or small ornamentals already grow in the neighborhood.
When I’m walking around town, if I see by a california poppy going to seed I’ll grab some seed heads and sprinkle them in tree planters as I pass by. They’re pretty, and easy to remove if someone decides they don’t want them there.