As Howard says the angle of view can be better than a conventional plunger type in many machine set up applications. Especially if you have the full set of Starrett (or other make) accessories. Ultimately the standard plunger style indicator is intended for quality control purposes when mounted in a stand rather than machine set up. Which doesn't stop it doing a perfectly good job when needed but I suspect folk who have properly learned to exploit the back plunger type may get along a little better.
Hafta say I grabbed my Starrett Last Word set with all the bits very cheaply (probably due to it being stuffd into a three layer pencil case rather than a proper box) maybe 30 years ago thinking "This will be very useful.". Yup so useful that I've literally never used it! That said my 5 standard stye ones average around 2 or 3 outings a year at most. The lever types and Blake Co-Ax knock off do all the heavy lifting.
One thing in the set that really out to be useful is the "extender seesaw" thingy which can be poked something approaching 2 1/2 inches down a bore.
Clive
Edited By Clive Foster on 20/01/2020 21:56:05
Edited By Clive Foster on 20/01/2020 21:56:22