Hi
Because I do all my own audio myself (so it doesn’t matter if I chop up my audio tracks willy-nilly) I use the razor and crossfades to mark the passages where I want the track level to alter, then use the Modify>Audio +dB or -dB commands – from the keyboard, to take the level up or down as required.
I only resort to using the pen tool on the rubber bands to cope with the very ends of a track if the transition is too complicated for a cross-fade.
It means my project looked at in an EDL/OMF/AAF looks like confetti – but thats not part of my workflow,
The big advantage is that the crossfades are very easily shifted earlier/later on the track if say the voice over or dialogue is altered and the dip-under position changes.
I also use it for GarageBand-created music tracks where I make a full-on version and an underscore version. Putting both, in sync, onto one audio track means I can easily manage the music character-changes just by slipping the crossfade between the two one way or the other.