Now the main wonder isn't why he chose to spend his money on that bike but why he chose to commute quite slowly on it when he would have been much more comfortable on a different style of bike.
I used to do this- not on a 6K bike! (more like £600)- but a TT bike nonetheless.
I'd ride to work really easy and go train after work some days (I'd hide my courier bag with my work stuff in a bush by the side of road I trained on).