Does a 401(k) plan provide a disability benefit?

Soon, “a plan providing disability benefits” must design its claims procedure to meet some conditions ERISA’s claims-procedure rule does not otherwise require for a retirement plan’s claims procedure.

https://www.gpo.gov/fdsys/pkg/FR-2016-12-19/pdf/2016-30070.pdf

If a 401(k) plan has immediate vesting for all contributions and allows a distribution on a participant’s severance-from-employment (without considering how the employment ended), is it fair to say the plan provides no disability benefit?

Can anyone think of a situation in which a 401(k) plan’s administrator must decide whether a participant has a disability?

Vesting, 1000 hour and last day requirements are sometimes waived for Disability.  But I can't imagine this being called a disability benefit.