They called it dot and dab. Yes its easier to remove as its only in the corners with a spot in the middle. If it was applied to the wall with a notched comb, the adhesive would have covered a larger surface area of both tile and wall resulting in the 'proper' way. I wouldn't say it's a bad job if it 'did the job'
I have this mate who laid floor tiles in his hall using the same dot and dab method, except his made different 'notes' when you tapped on them and over time, a few cracked as obviously, parts of the tile were hollow underneath.