You do not need to restart to enable or disable EAC. Well, so long as you're not running Windows 3.11 on top of DOS 6.22. EAC does not normally run all the time, only when a game requests it to start. In other words, if you start 7 Days without EAC enabled, it does not start. If you start 7 Days with EAC support, the service starts up in the background and it runs.
My personal preference is to leave EAC uninstalled and disabled because, much like BattlEye, it has been caught running when games are NOT active and sending desktop screenshots out. Also, an anti-cheat does NOT need the same level of access to my system that a driver does. The last time I checked I cannot go to Best Buy and purchase a PCI-E card which does aimbot/wallhack/whatever in every game known to man. Most cheats are executeable files which the user runs. This means it runs in their context, not as a driver. I have yet to see a cheat that runs as a driver.