It looks like this is a dual SIM phone they are selling. They are more popular outside the US. And in this case, that particular phone is NOT compatible with Verizon, Sprint or other CDMA phones. Earlier this month, I went through the process of buying a phone (Moto Z2 Play) and signing up for a Verizon prepaid plan (Wish I had discovered this about 5 years ago). I made a point to buy a phone that was compatible with all major US carriers. It was a bit more expensive ($30 or so) but I can move to any carrier in the US.
BTW, this phone gets good reviews.