You can move through town quickly!
I regularly ride bike and I see it as one of the fastest transportation methods within central Tokyo. You cannot beat bike unless you are going from a railway station to another station.
The only catch is that some places are very strict about parking on the street. Just after 30 minutes' stay, with your bike secured to a walkway railing, you may find a ticket tied to your bike, or it might even be towed away. That said, I suggest checking out bike parking available at your destination.
I want to say something about "decoration" of bike, but sorry, I am not big fan of it myself...