Breakers are often used as switches. Per the testing requirements of UL 489 breakers must be designed to pass a series of tests which include a minimum number of load an no-load operations, i.e. endurance tests. Usually the larger the breaker the lower the number of operations.
For example the reference that I have includes:
Breakers 0-100a, 6000FL, and 4000NL @ 6/min.
101-225a, 4000 and 4000 @5/min.
226-600a, 1000 and 5000 @ 4/min, etc.
Also, the life of any accessories must also comply.
Incidentally, for 120v and 277v breakers for the switching and protection of fluorescent lamp loads there are additional requirements which include a 3001 operation test followed by temperature tests at various prescribed intervals. NEMA AB3 does define the application as I recall.