jesterselv,
All the points you made have nothing to do with the technology (TVI vs. IP), but about the brand you are using. Everything you said about your TVI brand you are using, is the exact same with a similar IP systems:
Camera choices, auto NAT, etc. have nothing to do with the camera technology.

As far as network traffic goes, most of the Hikvision OEM IP systems have built-in switches with POE and auto VLAN. You simply plug & play (like you would on a TVI system) and you are done - and no IP traffic on the main LAN. Plus do not have to mess with the separate power supply of coax cameras.
It is only when you go above 16 IP cameras, that you have to do your own POE switch and configure it.

IP camera systems have several advantages over coax however. Higher resolution cameras for one. You can have clusters of cameras on a building, then send it over to another location with just one cable. And fiber between buildings (or remote locations like a gate) is a lot easier than all the black boxes you would need with coax based systems.

Coax based systems ONLY have 2 advantages. Price for those entry level systems. And when upgrading a system that only has coax w/power to each location.