When I started brewing I used to dump the lot into the FV because I knew no better.
Fairly early on I switched to letting the crud settle out before syphoning only the clear wort to the FV (I think the original reason I made this switch was because I got into harvesting yeast).
This got easier when I switched from a stock pot on the hob to an electric all in one with a tap - the crud magically settles just below the level of the tap!
One other thing I did/still do is collect the crud in a sanitised bottle and leave it to settle out in the fridge. 1.5-2.0L crud would typically net me about 0.5L extra wort that would be added to the FV within about 12-24hrs of pitching (you might say not worth it but when you're making smaller batches I'd say every drop counts!).
More recently I've started experimenting again with adding all the crud to the FV. Why? Because an accident involving a lack of kettle finings forced me to do this and resulted somehow (wish I knew how!) in a deliciously hoppy beer.
I haven't noticed any difference in clarity as a result of adding/not-adding the crud, though I've always struggled with chill haze no matter what I do so have to resort to gelatin or kieselsol.
One measurable difference is I'm consistently seeing slightly lower FG (by 2-3 points) and lower final pH (e.g. 4.2 vs. 4.4). The resulting beers are a little drier and more crisp which may or may not be a good thing depending on what you want.
In a feat of temporal engineering you actually answered your own question ~6months ago when you posted this link:
https://www.mbaa.com/publications/tq/tqPastIssues/1986/Abstracts/tq86ab10.htm
I think we've discussed this elsewhere before but I suspect the reason I'm seeing greater attenuation when I add the trub is it makes it easier for the CO2 to bubble off and hence the yeast are happier.