Anybody who beleives that ipp: in the UI is less confusing that http: has
clearly never met a real user.
A real user sees "blah-blah-blah-ya-da-ya-da-ya-da" when the see a URL. They
have no idea what any of it means; they dont care. The vast majority of
users dont even get "directory/filename"
An IPP client will probably allow people to type in "megacorp.com/printer1"
without any IPP: or HTTP: or port number.
Nobody is going to click on an IPP URL in a browser - i.e. the URL used to
actually send print to it. What would that mean? If they do access it via a
browser they will click on something that switches them to a client
('printto:megacorp.com/printer1'), downloads a driver
('http:...../selfextrcat.exe') or opens a web page from the printer
explaining what they should do. (Actually I quite like 'printto:' - what do
others think).
Saying that IPP lets me know that its a printer is an excuse for bad design.
Any UI that expects people to differentiate by hovering over the link and
looking at the status bar is broken.
Nobody is going to put printer URLs on their business cards.