TS55 splinter guard vs normal window

[Chinski]

Apologies if its an obvious newbie question - but while I read everywhere about the advantages of the splinter guard as a replacement to the normal piece of perspex in the ts55, it makes me wonder why Festool bothered with it instead of popping a splinter guard straight in there.

Am I missing something?

Thanks,
Chinski

 

[DynaGlide]

My guess would be that the green splinter guard is sacrificial, the blade cuts into it, and you may not need a splinter free cut on the offcut material. Hence the clear viewing piece which the saw does not cut into.