I already have a visitor travel card to get around in london for my stay. I noticed that a 24 hour ticket for big bus tours is 15 pounds…that seems a bit steep since I already have a way to get around. I just wanted to hop on a double decker just to say I went on one (yes I can get touristy). Are there any advantages to getting a 24 pass that I am overlooking (considering I already have a 7 day unlimited tube use pass for central london)