It's smart marketing. People in crypto don't seem to respect their privacy enough to skip these promotions. If we look at Blockchain's promotion, it has turned out to be a great success for them, and so will it be a great success for ShapeShift.

The people who hand over their personal information to ShapeShift then have a fully verified account, which means that they can use that platform without any hassle moving onwards. This is exactly what ShapeShift is after. Admittedly, ShapeShift is quite a useful service so people will love using it to convert crypto back and forth.