That is not to knock other techniques. I have used them and have a lot of respect for them.
Having said that this is why I love thumb walking as a technique.
1) It allows you to vary your pressure precisely to accommodate all kinds of feet. You can remain just inside their "comfort zone" and not add unnecessary stress to them.
2) You can get a feel for the "terrain" under the skin. Touch stress cues can be difficult to find. I find all kinds of stress cues such as what the Germans refer to as "hard tonus" to stringiness.
3) People often comment that I seem to know where sensitive areas are before I hit them. therefore I can lighten up just prior to the stress cue so as to not send them through the roof. I can also get a sense of what part of the stress cue is the most sensitive.
4) There a soothing smoothness to well executed thumb walking. To me it is like sculpting the foot or hand. I feel the shape of areas.
5) You can feel change in areas as progress is being made. I have asked if a certain problem has improved and people are amazed that I know.
6) You can make a detailed assessment of the stress cues. The value of this is hard to measure. People will see you as more professional and knowledgeable.
7) Done right the thumb walking technique can be much easier on your hands.
8) With thumb walking it is easy to lay down a consistent pattern.