Because that's one of the easiest ways to tell which version you have (V1 and V2 have yellow subs, one of which is in frame while the other is in the letterboxing, and V3 has white subs in the picture, replicating the theatrical subs).
The italics part sounds off to me, though...I don't think any version of Dark_Jedi's GOUT restorations used italicized subtitles...