Falcon and other PQ crypto hasn't been time tested. Just like SIKE that got broken in a classical computer, it's possible newer vulnerabilities may be found in lattice and other PQ crypto schemes.
Why should this feature exist?
As a mitigation for short term till PQ crypto proves their resilience to classical computers over a period of time, it's advisable to yse hybrid cryptography, such as requiring ECDSA+Falcon (classical+post-quantum) for signatures.
Implementation
Do you have ideas regarding the implementation of this feature?
Are you willing to implement this feature?
The hybrid signatures, keys should be self-contained and shouldn't require clients and other parts of the application to handle two different set of keys.
Rationale
Falcon and other PQ crypto hasn't been time tested. Just like SIKE that got broken in a classical computer, it's possible newer vulnerabilities may be found in lattice and other PQ crypto schemes.
Why should this feature exist? As a mitigation for short term till PQ crypto proves their resilience to classical computers over a period of time, it's advisable to yse hybrid cryptography, such as requiring ECDSA+Falcon (classical+post-quantum) for signatures.
Implementation
Do you have ideas regarding the implementation of this feature? Are you willing to implement this feature?