Because there is no "standard" way of quoting power ratings, and while RMS is preferred by most, it is at best, inaccurate. Even then, wattage and volume aren't as closely correlated as people think. Anyone will tell you, Trace Elliot watts are far louder than their competitors. So, with the lack of an industry standard, why not quote peak ratings? They're probably the most accurate, and Bugera are far from the only ones doing it. Even high end manufacturers like Trickfish quote peak ratings. Plus it sounds far more impressive on marketing gumph, which doesn't hurt.