Ya, I suppose I should be buying footwear for the longer rides, not necessarily the 2km ride. I plan on doing a lot of weekend joyriding so perhaps I should be tailoring my choices to that style, and just wearing my normal shoes to work.. I mean, I go through 4 stop lights, in 2km, I barely hit 50 kmh when I drive my car..
IMO I would invest in a good pair of walking shoes and walk to work. As you mentioned, 2km is a very short distance to ride and warm the bike, unless you perform full warmup (which I am guilty of not always doing ). Enjoy your longer weekend rides with level of protection that you feel comfortable with.