What’s the advantage to VFR aircraft in not requiring an airways clearance? Does it save money?
A broad practice behind Class E airspace if it is being used in the spirit it is meant to operate as, is that if the conditions are VMC that arriving IFR aircraft will cancel IFR and look after their own separation. An assumption is that if IMC conditions exist, there won't be any VFR operating in IMC in the airspace. Assumptions aren't cool in ATC or in a cockpit.
Just say 2 IFR aircraft are operating in Class E in a layer of cloud, between 6000 and 2000ft, the aircraft will be subject to positive separation from an ATC. Just say a VFR aircraft can operate
legally in VMC at 75000ft in that Class E airspace. The airspace allows the VFR aircraft access to that airspace without a clearance. It frees the ATC from providing that clearance service, more time spent allocated to separating IFR aircraft. Less hassle to the VFR aircraft. If there is surveillance in this airspace, the ATC will
'see' the VFR and pass traffic to the IFR
if required. The controller may even attempt to contact the VFR to gain it's intentions so they can be passed on. Hell, the VFR can also ask for a radar service whilst in this, or any other class of airspace.
VFR aircraft avoid controlled airspace in this country like the plague. For good reason, it is virtually impossible in some scenarios to get a clearance. VFR pilots (especially if they're low experience pilots) are intimidated by ATC. There are other reasons why but it upsets some people's sensibilities to hear these reasons.
The Class E airspace allows more access to airspace to VFR than they are getting now.