Because it was designed to be used for both rhythm and lead The TTS is a combination pedal that does Clean boost, Clean Drive and Overdrive all in one neat package.
Unlike Tube Screamers and their clones the TTS has a fat bottom- ended sound, a ton of drive & volume to spare. Now with the boost adjustment for adjusting the amount of drive you want the TTS have in Boost Mode!
Texas Two Step DLX (TTS-DLX) The TTS is an over drive pedal with an added boost switch that was added to lay fills on top of a broken up rhythm tone. Originally the TTS was designed to get a Fender Twin Reverb amp to sound broken but it pretty much has been used with just about every type of amp made at this point. This pedal has more bass than a standard Tube Screamer in rhtym mode and an eq shift with added gain, level and drive in boost mode. The boost mode is adjusted via an internal single turn trim pot which is pretty much a set it and forget it type of thing.