No I don't think that's a mistake. I suspect the probability that someone who has recently bought an item buys the same one or a similar one again is pretty high.

People buy stuff for others. People buy stuff for professional reasons. And yes people do need more than one faucet when they are building or redecorating a home for instance.

Also, showing people stuff they have recently bought may provide an incentive to recommend it to others or write a positive review online.