It depends more on your gear. Without explaining all of the intricacies of PVP builds, which would frankly need its own guide, you're typically looking to hit certain attribute perks with your build. If you have well-made gear equipped that is crafted by a high-tier armorer thrall, it may be possible to get the stats you need with just the clothes you have and a spread of buffs. War paints can give you the extra few points you need, but they're by no means necessary for combat. So, if you're having trouble paying for the dragon powder necessary to maintain your war paints, feel free to leave them out of your builds and save yourself the time.