I'm in the process of rewiring my 1970 Willard 36 including a new main panel. Old panel had three 50a breakers ganged together for windlass, including 2/0 cable run to panel, a huge waste and bulky. I am installing a surface mount BSS 150a breaker - same as your link - inline between battery and windlass. Also inline is a simple switched solenoid which is powered off a 5A circuit breaker on the panel. This shortens the cable run significantly and cleans-up back side of panel.
Regardless, the BSS breaker will almost never be used under load so the warning is not relevant. Though if it trips, you may have trouble resetting.
I was once told by a credible source that in general, breakers should not be used as switches though I forget the reasoning. Probably makes sense to have panel switches behind the remote breakers, though I have rarely seen it done except for lighting and ventilation/fans for convenience, or items with intermittent usage such as manually switched shower sumps.