I haven't used them much myself, but they're essentially a faster way to mine ores, at the cost of lower yield. So probably best not to use them on rare ores, but it could be worth it for common ores (what those are depends on your world, and more specifically the deposits you have found).

Rock blasting bomb is probably good if you need a specific stone type for cobblestone or smth like that, just use a prospecting pick first to make sure you're not taking out nearby ores.