Mary Haas's IPA transcription

In my "linguistics for teachers of foreign languages" class, my professor is using IPA transcriptions that I am not familiar with for California English vowel sounds. For instance, the word "bay" is transcribed as [bey]. I would normally transcribe this as [beɪ]. Another example: for "go", she has it transcribed it as [gow], where I would transcribe this as [goʊ]. 

In her class notes my professor credits her IPA transcriptions to Mary Haas. I looked Mary Haas up, and apparently she is quite famous for creating a kind of alternative IPA for the Thai language. What I can't figure out is why my professor would use this alternative system to transcribe English instead of standard IPA. Any thoughts?