Eddie brought up a good point. Casinos Marketing bases their offers on accumulated EV.

Player A spent two days at the property. He/she ran a total wager of $20,000 on a slot with an 8% house edge and won $1000.
Player B spent two days at the property. He/she ran a total wager of $20,000 on a slot with an 8% house edge and lost $1500.

What these two players won or lost is irrelevant. The pertinent stats are the total wager and house edge. The house accumulated $1600 in EV from each of these players. Marketing uses the accumulated EV as a basis to determine future offers to these two players.