I went on a Segway tour on the Freedom Trail in Boston, and honestly, it was hella fun. It allowed me to travel miles and see a whole bunch of historic sites that would have taken me the whole day to walk (or two days to drive, thanks to Boston traffic) (or never to bike, as I'd be dead thanks to Boston traffic).

Segway facts:

1 - It's really hard for you to run into anything on these unless you're trying. They respond to how you lean, so if you're about to hit something, you'll react, and the Segway will automatically stop.

2 - You do look hella dorky on one, but if you can get over your cool, it's cheesy fun (I had several bemused Japanese tourists take pictures of me as I scooted past).

3 - Unless you are using it to tour an area (i.e.: Freedom Trail), most people will never ride one to putz around unless they want to try it, and they'll only do that once. Canal Park doesn't support any type of spread out and/or interesting destinations that people will pay money to see on a Segway.

I did not say there was nothing interesting in Canal Park, just that they are all located close together and very accessible by walking. Unlike a longer tour, there's no reason someone would pay money to tour the public sculptures when they could walk it for free.