I regularly take one from Victoria to Vancouver. Live downtown and people on the other side are near downtown in Victoria. So much quicker and more convenient. Only downside is in truly bad weather (fog or very low clouds), you can have problems. And they are limited to daylight hours only (VFR flights). Definitely worth taking at least once. If you really need to cross, you always have the heli - but this is considerably more expensive.

For the floats, one company allows you to sit in the right hand seat as they only fly with one pilot. Very different view.

As far as being regularly scheduled services, the float plane companies now have flights to:
Vancouver airport
Langley
Nanaimo
Seattle (out of Victoria)
Gulf Islands (very limited)

The number of flights have steadily increased from what I can tell. So at least on the Canadian west coast, scheduled float planes are very popular. The downtown to downtown run without the security hassles of going to the airport and without the added commuting time. Likely won't work in that many places (capital located where your choices are flying or taking a ferry from the main business centre of the province located on the mainland), but it is definitely a very viable and vibrant service.