WAP is in use in all cellphones. At least partially. Did you buy a ringtone and got a message on your phone to download it? That's WAP! Did you send or receive a picture message (MMS)? That's also WAP (the message transport at least).
So, WAP is still very much in use and an integral part of carrier infrastructures. Without it billing systems would break and some proprietary systems would need to be built. But because WAP is a standard, you can buy any brand phone and it'll just work with your carrier and you can keep buying pictures/ringtones and sending picture messages.
That phones also add regular "full" browsers these days is irrelevant as it's just additional functionality. Companies like Winwap still provide the worlds Android and whatnot devices with WAP Stacks that let's carriers make more money on useless ringtones and pictures that we all love so much...
