Sometimes I wonder if it's about returns. "You bought one washing machine, but you might not like it and return it, so how about these others". Could even be that they're tracking sales only rather than sales minus returns, because returns take longer to come in so the metrics are harder to track.

The thing is for every 1 guy that just purchased it, the retargeting is getting 99 people who just looked at options and haven't purchased yet. So even if that 1% will never buy again in a short time, the whole cohort is still many times better than random non-retargeted people.