As the other dude said, the sensation releases endorphins which gives them a bit of an adrenaline rush, and enough of it can opt for a hallucinogen (ghost peppers are known to do this). There's nothing wrong with getting a bit more stimulation outside of what your tastebuds have to offer, but yes, a lot of people go overboard and do it for the rush solely and don't appreciate the food.
As for your case, you probably are dealing with generic hot sauces that are designed with all kick and no flavor, and often they fail to deliver on both counts. If you tried any local or specialty hot sauces (the good stuff), like some natural hot sauces, you'll appreciate the flavor it adds to the food, and the heat you experience should never get to a point where it washes out the taste but instead gives it kick that you can feel beyond your tongue. I don't mind tricking my body into thinking something tastes "potent" when I'm able to enjoy it.
I can relate to you. I have a rather sensitive palette myself - I tend to forgo sweet stuff, I love carbs (breads are my favorite food) and salty foods, and enjoy anything that tastes light. I believe it's because I have such a "distaste" for taste that I enjoy spicy foods so much. It allows me to appreciate foods considerably more without having to opt for foods that have such overbearing taste to them. Maybe it does muffle the taste, even so I wouldn't be bothered, and would in fact prefer it if it means not having to deal such foods on their own. I for one cannot see myself eating mexican food covered in cilantro if it wasn't for hot sauce taming that bitterness (and perhaps accenting other flavors to boot).