Its more sensible to use other means of transliteration and transcription.. The 'Chat Alphabet' is amazingly ugly!
Words like - 3a66ar, 5"air, 7a88... They look almost comical!
Numbers just don't have any rightful place in serious linguistics.. Plus this use of numbers to represent Arabic has its strongest support from the ultra-nationalistic Christian Lebanese, they are pushing for it to replace the Arabic script in Lebanon and have been doing so for some time. If you travel around Beirut you will see scores of billboards written in this alphabet of theirs.
I was able to learn Arabic as a non-Muslim, I'm sure every Muslim will benefit much more by learning the Arabic alphabet rather than any alternative to it. 9a77..? 2allahu 2a3lam...