Keep in mind the call collect number can only be used on LANDLINE if you call from aboard. Some bank reps know about it some have no clue. (I have some bank reps told me this critical point when I called to initiate travel alerts, other reps would just repeat the parrot line of "you can always call us direct by such such number at the back of your card."

It would not work on VoIP set up. These days even hotels are using VoIP systems for their properties - and it would NOT get you the collect call through. I have had that issue in London and in Rome.
Hotel FDs made the calls for me from their own phones.

FYI, in the case you need to call because your cards were lost/stolen/compromised, you can use SMs which work just as effective and much easier.

Then of course you can use Skype etc to make the toll free calls and totally bypass the collect call route.