Personally I think its a poor choice to go with ID.me instead of login.gov when it comes to security. Primary reason is the completeness of the product and reliability. A security product does not needs all the bells and whistles and can be well defined for governments use case. Any security product with ongoing development is just an open door for possible vulnerabilities being introduced.

In our NIH-related project, we were offered both.

For IAL2 identity proofing, Login.gov is only for US persons, i.e. validating US-issued credentials. Meanwhile. ID.me has support to validate foreign passports.

So, if TreasuryDirect supports foreign customers, it makes sense to offer ID.me, but it seems inappropriate not to offer Login.gov for customers who are US persons!

Does login.gov require photos, videos, fingerprints, smartphone apps, or similar nonsense as ID.me does?

Or does it offer less invasive ways to confirm identity, like mailing a code sent to one's long-established postal address, or an in-person visit to a local social services office?