Adjusting audio waveform volume Vs channel volume

Cubase
1

Hi was just wondering what advantage or disadvantage is associated with changing the volume of audio waveforms via the draw tool in the arrange window as opposed to automating channel volume?

I have recently discovered the draw tool method and like it because it seems to be quicker and easier to make detailed changes but i wondered if there was a disadvantage to doing it this way?

2

-Look at the signal flow that would be the first difference.
-Try to draw a +6 dB gain with event envelopes.