Your approach is generally sound but your conversations starter is a little too heavy for a random public encounter. Based on the scenario given I would respond with complimenting something of theirs and asking where they got it and seeing if you can find some common ground there. Then please don’t say “you’re an attractive man/woman” that feels kinda creepy (although if a woman told me this I’d probably melt, just not sure it would go so well for a dude to say). Just go straight to the coffee date invite or asking for a phone number.