I believe that's opt-in. At least it seemed to be when my landlord switched to Bilt.

There's a section of your Bilt profile that shows your other credit cards and whether you want them linked. It's pretty freaky to see them listed in the first place.

I definitely keep them off.

Bilt is ultimately a big points/reward program though, so you might get points for having them connected.

I still haven't figured out exactly what Bilt's business plan is, but the main part seems to be trying to get as much financial data on people as possible, and partnering with landlords to do so, and since it's how to pay your rent you can't unenroll completely. (Unless you maybe mail your landlord a paper check?)