Oddly enough I used a simcard I have in a dongle to go through the WeChat verification process for the wifi only Nexus7 so whyWhatsapp require a sim card cell number - does not work with WiFi only devices
Although I have seen hacks that port a cellphone installation of Whatsapp to a WiFi tablet
To much hassle in my opinion
whatcrap can't offer the same thing is beyond me.
Whether or not I'll stick with WeChat when BBM arrives on the scene is currently unknown but for now…