It's not an advantage unless your competition are also discounting their product. If a particular product is in great demand you don't offer a discount as cutting your bottom line is a pointless loss of revenue.
I suspect they have too much stock, they placed their bets at the start of the generation and now need to make room for other things.
It, as a singular occurrence, makes no statement about the health of the XBone. It just probably exposes bad stock control on their behalf.
Of course it's an advantage if people come to your store to buy stuff from you instead of your competition because your prices are lower.. That's how a free market works. I'm surprised you're even trying to argue that point. It's basic math...lower prices will bring in more customers...just look at gas stations...they all sell the same thing but most people will try to find the stations with the lower prices even if it's only a few cents...