Having used suppressors for years, they were a necessity long before they became cool. The reduction in recoil and the reduction in sound simply made most shooters better. The only downside was the length of the barrel and change in point of impact. These issues have been addressed, with shorter barrels and suppressors made from lighter materials. So, when it came time to look at entry weapons the advantages seemed obvious as well.
Suppressing entry weapons or even patrol carbines is a bit of a different story, especially with any of the AR platforms. The suppressor generally adds backpressure, which affects cycling, increases fouling, and can make an otherwise reliable rifle unreliable. They also tend to change the point of impact considerably. It is no easy task to change your sights for suppressed or unsuppressed, and you sure cannot do so in the middle of an operation.
The shorter the barrel or the more powerful the cartridge, the harder it can be to make them work. They add length, which can defeat the entire purpose of a carbine. But, being able to shoot without ear splitting noise is a tremendous benefit, as well as the lack of flash. But, unlike bolt rifles and precision rifles, the trade-offs are not always there. Moves to the 7.62mm rifles make it even more of an issue, as there is more pressure, more fouling, and sometimes more recoil.