I'm surprised this works for pronunciation: surely it's easier to emphasize the first syllable and then add syllables with soft or altogether lost vowel sounds (-es, -ed, -able etc.) rather than starting with clearly enunciated suffixes and then progressively de-stressing and mangling them I'd be more comfortable going from com- to comf't'bl than from table to fort-abl to comf't'bl

For the exact same reason I can see how your method works well as a means of teaching spelling by forcing native speakers to voice all the vowels that native speakers replace with the -schwa sound when pronouncing the full word.