(the benefit from this is for the companies). Normally this is in the form of applications you install seem to want to install a toolbar, some however may well make an offer to help/improve your browsing/searching, etc. Toolbars however, many of these are self inflicted, they in most cases require a degree of user cooperation.
Since I also have MBAM Pro, which compliments avast, I don't see the need to do this and guess what I haven't had a single detection on MBAM Pro (and I don't really expect to). If you are comfortable with making those decisions, know what is legitimately on your system and know what its purpose is, then there would be no problem in increasing the sensitivity and also scanning for PUPs. I may well be one of the exceptions to the rule in that I know what is installed on my system and if I did enable for scanning for PUPs should know what it is about to make a decision on an action to take.
Personally I haven't changed the settings in either my on-demand or on-access scanners (other than the web shield) to scan for PUPS.