Maybe avoid mention of hasEnrolledInstrument for now?

[marcoscaceres]

The architecture doc says:

Furthermore, the "hasEnrolledInstrument" method enables merchants to determine whether the user can support SRC payments, especially valuable in a guest checkout scenario. Merchants do not have access to this type of information through other means.

but "hasEnrolledInstrument" remains controversial from a privacy perspective.

[ianbjacobs]

I'm ok to remove it from the benefits section. However, I think it's important to leave elsewhere in the document (e.g., in the flow descriptions). If we change the spec we should update these materials.