If I was a cynical person
I would think that Best Buy made a small but loud move into the UK looking at spending a relatively small amount but giving the impression it was in preparation for a larger venture. This would surely lead the major competitor to suddenly spend large amounts on updating their stores and flashy advertising when they already have profit issues.
If Best Buy were then to "sell-up" at Christmas time and flog the inventory you have, at a price that undercuts their competition at their peak time, this might cause the competition to then be in very vulnerable position and ripe for take-over and a nice easy way to spread nationwide in established locations should it be purchased.
But of course I am not a cynical person.....