I have booked a number of O excursions on cruises that we have taken. We have never taken a "package" that O offers. IMHO the prices are "crazy" just as the hotels (even with transportation included) are that O partners with in various ports. We prefer to leave the ship at the time we want to venture off & at explore at our own pace. The guides we've been with walk at a very reasonable pace, especially for absorbing the surroundings.
If the port is within walking distance of the town/city and we've never been to it before, we will explore it on our own. However, for various reasons not everyone is comfortable exploring on their own. We do sign up for O's excursions if transportation to a place we want to go to is either not available or getting to it from the port is not convenient or possible.
With all that said, I think the packages are very good for passengers who don't want or don't have the time to do research on options getting to places and checking out the "must sees". It's much more relaxing going on O's excursions when you are picked up at the ship, driven to your place of interest, given a tour, & then driven back to the ship.
Lastly, I have never had a problem financially with the payments for tours or use of cruise credits.
There's no "right way" that fits all. Each to his own.