I frequently read about a widely accepted/presumed bias existing in the art world that somehow watercolor is a "lesser" art than oil painting. Or has been thought so in the past. Let me say first: I love both, practice both, and master neither.
But to prefer one over the other would, for me, be like choosing peanut butter over jelly. Fall over spring. Red over black. Unthinkable. Oil painting is luxurious; watercolor is effervescent . Oil painting is certain; watercolor is serendipity. Oil painting is a deep, sensual laugh; watercolor is a giggle.
Practically speaking, you get do-overs when painting in oil. The pigment stays open longer and you can blend, reblend, adjust values, shift things around the canvas; in fact, you can (and I do... frequently!) just scrape the whole mess off and start anew. Infinite chances to work on a nose or a bloom. The artist is only limited by personal patience and tenacity. Leonardo da Vinci said, "Art is never finished, only abandoned." I think he was talking about oils.
Watercolor. Sigh. So sparkly. With watercolor you really have to work to get a second chance. Once pigment meets paper, it is resolute. Oh, there are the proverbial tricks of the trade but the artist always has to barter a bit of spontaneity to use them. When working with watercolors I have to plan, plan, plan and even then, there is such an element of surprise. A big plus for me: watercolor is so portable. I've always got a studio in my purse. That leads to spur-of-the-moment sketches like this Pride of Barbados.
Sunday Morning in the Garden
ink/watercolor in Moleskin