No it's not. Discs are virtually two dimensional and are used solely for braking and nothing else.

My first winter commuting I glanced off the side of a car because my V brakes packed with snow(car's fault,cut me off). Shortly afterwards I got a disc bike and my bad weather commuters have had discs ever since. My first polo bike had V brakes(same bike as above) and my front wheel got ran over by another rider. Had to ride home without a front brake because the wheel tacoed. My other polo bikes all had discs. I've gone through a set of rim brake pads in a month,my disc pads last much,much longer. My disc wheels are cleaner and there's zero rim wear. My rims don't have to be perfectly true for maximum braking. Disc pads are much easier to change(unless you've got cartridge pads) and easier to set up(distance to rotor only,no height,yaw,or toe-in).

Does everyone need discs? No. Are they right for every application? No. But there are def times when they are far superior to other systems.