I have an old Pioneer gourd calabash with the pressed meerschaum bowl. I keep it, and smoke it from time to time, because it provides a unique, cool smoke, imparts no additional flavor to the tobacco, and is much lighter to clench than one would think. Tobacco is a finicky substance: what smokes well in one pipe may be horrible in another. So, my gourd calabash is often used when I have a tobacco that seems to burn too hot or tastes bad in other pipes. Sometimes I smoke it just to be different.
The best way to keep them clean is to take them apart, and use dry cotton balls and paper towels to swab out the inside of the gourd. I don't moisten them, since the inside of the gourd is dry and might absorb the moisture and start to rot. The stem and bowl, of course, are cleaned like other pipe parts.
My personal outlook on it is that a piper should experiment with different types of materials and styles of pipes, as well as the different tobaccos, to find the best combinations that result in the most enjoyment of the experience. Fortunately, if one doesn't like a certain pipe, or a particular blend, there is a market to sell or trade nearly everything. I enjoy smoking my calabash, but it is a bit unwieldy for everyday use.