For those of us who do not have the ability to test boards. The numbers are all we have, so I would say they are VERY important. SL or GS is also, but they just reflect the sidecut radius. I realize where you are coming from, but it isn't the same place as me.......
Let me clarify this a little.
Since you used audio. The way I look at SCR is like amp power vs. speaker efficiency. If I am trying to buy speakers to go with my 5 W single ended tube amp, I will not be looking at something with an 85 dB/M efficiency I need something around 100 dB/M. How these sound is something you need to hear to decide, but it will at least tell me what may or may not work for my application.