The points made by the proponents were all good. Notable, that suppressors do a great job of bringing the ear-damaging sound made a muzzle blast down to a safer level for a shooter and whoever is with them behind the gun--whether that is a coach or hunting partner. At the same time, suppressors do nothing to diminish the sonic boom of a bullet from a hunting rifle--negating their effect as a "poacher's tool" for hunting undetected.
If you don't want to take my word on this, give this study a read. It was conducted in Finland in 1992 as a joint project between Ministry of Environment and the National Board of Labor Protection and backs up the claims of suppressor advocates with cold, hard facts.