Many challenger banks aim to distinguish themselves with an intuitive and simplified banking experience. In large part, they seek to distance themselves from the staid reputation of the traditional banking industry and appeal to customers with digital-only offerings. These banking solutions are designed to meld into everyday life similar to other social- or commerce-based apps. Many offer more streamlined and timely activities such as account opening in a matter of minutes, compared to days with an incumbent bank, to more accurately align with the reality of consumer expectations.
the relevance of such an additional crew member is limited if an army really goes all-mobile warfare and establishes a 2nd crew for every tank.
The Germans had 2nd crews in May 1940, which successfully helped against the problem of crew fatigue.
Nowadays it would be less about fatigue as the internal space of a modern tank is less hellish, but it would still help a lot against sleep deficits, against the maintenance burden and it would allow commanders to replace the men who turned out to be duds in combat (it happens, no matter how they excelled in peacetime training).