Supermoto Cornering - Why All The Sliding? Does It Help Or Hinder?

This is something that I've been thinking about on and off for a while.... is the supermoto "leg out/backing in" style really the fastest way for those guys to get around a track? I haven't yet tried to get into this discussion on a supermoto forum or with SM riders in real life, but I am guessing it would be quite an... interesting discussion. 

Some things I've noticed that seem to be a recurring theme:

• Supermotos "turn faster than sportbikes". This one I can understand as being confused for "easier to turn". IMO if a SM (supermoto) rider can't turn a sportbike equally as fast as their motard, they either aren't putting in enough effort, or just need to develop their quick turn ability to a higher level.
• Supermoto requires some kind of special rider training. On a couple of SM forums I visit there have been threads asking about SM training. Most have a section dedicated to supermoto riding technique as well - as if the physics of a two wheeled single-track vehicle and other basics don't apply to supermoto? It's almost as if new SM riders try to skip the basics of cornering and go straight to corner entry, specifically backing it in as the key SM skill. Which leads to the main point...
• "Backing it in" is required for fast lap times on a supermoto.

So what is the story behind this? Why don't SM racers just use the good 'ole quick turn technique and a later corner entry? From what I have seen it always looks like they're sliding for quite a long distance - is this because a SM is a tall bike and regular vertical braking isn't as effective because it would lift the back wheel off the ground too easily? If they weren't backing in I would straight up label it lazy cornering...  Or would a quick turn upset the bike too much because of soft & long travel suspension (don't forget they take some sizeable jumps as well). The other thing is that maybe backing in allows for safer trail braking? (AFAIK "proper" backing in relies on using the front brake and engine compression, not locking the wheel with the rear brake.)

I also read an interesting bit of info that said putting your inside foot forwards can add an extra 20lbs of weight/traction/grip to the front wheel when cornering. Does anyone have thoughts on that? Initially I put it down to a habit being carried over by dirt bike riders, but maybe the light weight of the bikes could make extra weight transfer towards the front more of a necessity? Or maybe it also makes it easier to control the rear slide that way? There seems to be a general idea among SM riders that it doesn't matter where your rear wheel goes, as long as your front tyre has enough grip. Part of me thinks that they slide the rear whenever they can, just for the fun of it.

The other thing I notice is that the way a corner is ridden depends on whether it's a hairpin (usually foot down, backin in) or a fast corner (knee down or foot out depending on preference), or esses (usually feet up on the 'pegs from what I've seen). Supermoto tracks are also much smaller than road race circuits, maybe backing it in is more effective at slower speeds than higher speeds? They don't move around on the bike much either, maybe because of the short distances between corners? Or maybe they figure that there's no point since the bikes have so much lean angle available?

I have an XR400 motard that I've only ridden on the streets, but definitely no problems with front wheel traction there. But a quick turn does feel kind of awkward because of the tall seating position. For example there's much more movement (measured from the seat & handlebars) going from 90 to 45º than doing the same thing on a sportbike. Not sure how much the situation would change when ridden faster on a track though... I am currently building a KTM supermoto and I'm going to be doing supermoto track days (a quarter the price of a regular track day!) so I plan to experiment with some different techniques and see what answers I can find to all these questions. But I'm interested to hear any other thoughts. Has anyone here ever raced supermoto? Or have any of the Coaches had students on supermotos? - shared from california bike school