Seems spectacularly senseless to me but hey what do I know I'm only a pilot.
Class E is used almost 'E'verywhere in the US outside the busy terminal areas.
The greatest advantage is to be able to freely go anywhere without clearance when VMC. When the weather turns bad, use your IR - talk to ATC, get out your IFR sectional, file an airborne flight plan and get separated from everyone else. The guys who don't have an IR will be on the ground by now.
We have separate IFR and VFR cruising levels to address the problem you describe.
The guys flying IFR are always talking to ATC, so they will be asked to turn if there is a conflict with VFR stuff. The guys flying VFR are encouraged to get 'Flight Following' so you become known.
To prevent turning too much under IFR due to unknown traffic, there is also Class A over 18,000ft...