@Pooh451 If by "those guyz" you refer to Wally, Alice and Dilbert, I have a suggestion for why they employ portable personal computers rather than mobile phones.
As it turns out, much of the work we engineers do especially when designing chips, both digital (ASIC) and analog (MMIC), hinges around ("evil") proprietary software, for which the source code is unavailable. This software is commonly available pre-compiled for Windows and various UNIX-en, but generally only for IA86/64 (and sometimes SPARC) processor architecture.
Most mobile phones and similar platforms (iPad, I'm staring at you) employ the much less widely supported ARM architecture, and could not run such software without the extreme overhead of virtualisation or some "VNC" solution (in which case the overhead stems from network lag).