IPP's got a few problems, especially when it comes to phones/tablets or other mobile devices:
- IPP requires unique drivers for each printer. Some mobile devices (Chromebooks and iOS, I believe) don't allow installing drivers.
- IPP requires that you're on the same LAN segment, or that you punch a hole through your router. That doesn't work very well when interacting with foreign printers, and punching a hole through a router is too complex for many home users.
- IPP is limited to HTTP Basic/Digest auth, which isn't user friendly or secure. The traffic's also unencrypted. (And SSH isn't user friendly enough for home users.)
(Disclaimer: I work for Google, but not on Cloud Print.)
- IPP requires unique drivers for each printer. Some mobile devices (Chromebooks and iOS, I believe) don't allow installing drivers.
- IPP requires that you're on the same LAN segment, or that you punch a hole through your router. That doesn't work very well when interacting with foreign printers, and punching a hole through a router is too complex for many home users.
- IPP is limited to HTTP Basic/Digest auth, which isn't user friendly or secure. The traffic's also unencrypted. (And SSH isn't user friendly enough for home users.)
(Disclaimer: I work for Google, but not on Cloud Print.)