That's actually a sensible suggestion too to live with OEM seat covers for 1 - 2 years and then install seat covers. However, if seats are beige they will get dirty within 2 - 3months of usage itself (irrespective of running full time AC and maintaining well).
Only down side, many of us don't mind doing an initial investment since we would have planned a budget. However 1 - 2 years down the line, we consider it as a maintenance expense & hence try to avoid.
IMO, the art leather seat covers will most likely last for the life time of the car & hence good idea to install them when new itself. In my previous car I had installed gSport which lasted and remained like new for 5 years and 1.1Lakh kms.