Most appraisals, across the board, residential or commercial, are like a House of Cards, when the properties become complex, - built on the injection of subjective opinion at critical parts of the appraisal where solid evidence is lacking for one reason or another.
Sometimes it is indeed a very tall house of cards, invariably constructed inside complex Excel spreadsheets where you see DCF values injected from Argus, subjective percentage adjustment tables created by the appraisers, with complex dependencies between various cells across numerous sheets in the the Excel workbook/files. All held together by a kind of fragile thin chain of dependencies thread that can easily break.
Just imagine a large appraisal company with hundreds and thousands of such reports, from the far corners of the earth.
So, given the low pay, and fright of an appraiser who asks to many questions (or what have you), there is always a big demand for the "right" appraiser.
However, I would say in fact, there is more of a demand for analysts to support the commercial appraisers. - Everyone wants to be a licensed appraiser. But, the fact is, you are better off spending your time getting good at data analysis. You will have a solid future, as you can get better paying work in other domains.