I've never personally used white sage powder for cleansing, I've always stuck to the more traditional way: the dried sage bundle. The smoke purfies well, and it does an excellent job of cleansing me and the space around me, as well as protects.
You don't have to carry a bowl around you while you burn sage, but it could be recommended unless you want ashes all over your floor, or the area that you're cleansing.
If you feel safer with what you're currently doing with the sage dust, then by all means, keep doing so. It just depends on what you want to do and what makes you feel safe.