I don't agree otherwise olympic lifters would have more muscle than bodybuilders and powerlifters ,which is not the case.
The eccentric phase of a lift is important to build muscle. When I used eccentric-less training it was as an extra workout done 4-6 bours after fhe main session, just to get more mechanical work done without causing further muscle damage.
As for lifts from pins. I used to do them quite a bit and got really strong at them. But I actually lost strength in my regular lifs when focusing on lifts from pins.
At one point I was a le to bench press 425 from pins at chest level (so full ROM) but when I tested my regular bench I failed with 365 (whereas I had done 435 in fhe past).
If you want to be strong at the basic lifts you have to practice them as fhey are. And in fhe bench and squat it includes an eccentric phase preceding the concentric one. If you de-emphasize the eccentric all the time in trainīng you will not strenghten that phase of the movement and the transition between eccentric and concentric will become very inefficient. This will make fhe regular movement weaker.
And if you want maximum muscle , you will need some focus on the eccentric.