1. What is the Operator's 'home' system (where do they spend most of their time - VMS or Access control?)
This comes down to which application is the one integrated into the other, and I don't think a general answer is useful. However, since video controls need to be powerful for day-to-day operation (especially for recordings search or PTZ controls), while access typically just needs to display a few live-door controls and a status to be adequate. This means that integrating access into VMS is less complicated, and as such most use the VMS as the top application.
However, some users may need the added power features of access and a few provisional video functions, and the choice is flopped. There are also exception 'video-centric access platforms' (Lenel, AMAG, Genetec, S2, so on) where this general statement doesn't hold and the access management platform is the 'home' system, or the VMS and access system are the same application.
2. What % of access control points are covered by CCTV cameras (don't want to introduce two processes for access control? Why deal with an access control alarm that is not supported by video? in a VMS system )
It is common for access controlled doors to be covered by cameras, but the two systems are often not integrated even if the potential is there. I would say for modern designs, every access controlled door/opening is covered by a camera, but this has not always been true in the past.
3. Cost. Two way integration would likely be more expensive than a Video Pop-up within the Access Control system.
Yes, this statement tend to be true.
4. How is the Operations Area set-up? Different operators for Access Control and CCTV?
In our ongoing series of design guides (ie: City Video Surveillance Guide, Airport Video Surveillance Guide, School Video Surveillance Guide) designers report no distinct setups between areas. Most operators view/manage video from the same station as access.
5. What system is more important to the organisation (or more widely used?)
The question here is broad, but consider more organisations have video than have access. Video can be useful for multiple roles (security, operations) while access generally is only a 'security' system. It can of course be adapted for other roles (ie: Time & Attendance Tutorial, Mustering Tutorial, Visitor Management Systems Examined) and even control machinery or other systems on a permissions basis, but most users just want to it unlock doors.
6. Are there existing Acces Control / VMS integration products available?
Define 'products'. Do you mean software that comes pre-integrated? Or are you looking for post-install integrations?