There are some cases, in which it can be advantegous to delay some research.
Say for example, that you are having trouble dealing with a certain faction. You might want to avoid doing research, that triggers new, presumably harder, missions for that faction until you are better prepared.
Or you might want to continue doing some easy missions, that generate good income, before advancing.
But usually such considerations require a bit of prior knowledge about the game. No need to overthink this.
Your main concern is to be prepared for the alien invasion around January '99. That one happens no matter what.
Your goal should be to build up your organization to a level, that is equal to or better than X-Com at the start of the vanilla game by that time and also to destroy the cults.
If you haven't destroyed a single cult before the end of '98, you are doing poorly.
The tech viewer just says that it does SOMETHING, not what exactly.
It has been added, because people were seeing research topics that (supposedly) didn't do anything... and annoyed the living hell out of me asking why does it not do anything every other day... no other reason for its existence really.
I'm glad this feature exists.
X-Com unfortunately doesn't have a research preview description like many more modern games in the genre. You only know the effects of your research, once it is done. In vanilla X-Com that didn't matter yet, since all research topics were pretty self-explanatory and the research tree was rather small, anyway. Complex mods like Piratez or XCF, however, really benefit from being able to hand out some extra info.
Perhaps having it say "Affects mission/event selection" instead of "Affects game progression" would make it a bit clearer for new players?