Updating my original post on the Royalton Day Pass with more comparative information on the Jewel Runaway Bay day pass offered directly from
DCL. I did not visit from a cruise this time. Instead we did a week in Jamaica with our family of four DS9 DD5 and stayed at Jewel Runaway Bay. I even sought out some DCL cruisers to talk to around the swim up bar on June 14th. Yes, DCL cruisers are very easy to spot

So here is my comparison of Royalton vs. Jewel for the day.
Bus ride: DCL cruisers report the transfer time from Falmouth to the Jewel is 40 minutes so Royalton saves you ALOT of precious port time.
Water park: Royalton has expanded to include a second hotel and a lazy river since I have been there but Jewel's Lagoon waterpark is still better for kids IMHO.
Snorkeling: If your debating between snorkeling and a day pass at a resort then for sure go to Jewel. Right off the beach in shallow water there is reef and rocks to explore at JRB with schools of fish(feed them bread or vegetable fritters from buffet). There was nothing to see at Royalton.
Beach: JRB is by far the nicest beach I have seen on the north shore of Jamaica. Deep, wide, clean sand. Royalton's is good but I think the top layer of sand is imported there.
Food: Both have poolside grills with Jerk chicken, burgers etc.... At Royalton you will need a change of cloths to go into buffet in air conditioning. Jewel is all open air even in buffet so you can stay in your swim suite. Quality of food and drinks is equal.
Swim Up bar: At Royalton White Sands swim up bar pool is adults only(may have changed since new hotel opened), at JRB swim up bar welcomes kids and will happily make them virgin drinks. Also at JRB there is a shallow kids pool directly connected to swim up bar pool so you can supervise your kids while enjoying a drink.
In summary both are winners in my book and an all inclusive day pass is 100% the way to go with small kids off a cruise in Jamaica. Equal distance from port I would probably go Jewel based on the beach but with at least an hour of your port time lost in transfer I might do the Royalton again.
Side note if you really want to feel bad about how much you spent on a DCL cruise. A week at the Jewel in a standard room for 4 people with flight, transfers, food, drinks, non motorized watersports etc.... Can be had for $3830 including taxes off peak season. An upgrade to a plunge pool Jr Suite with Concierge service is around $4200 all in. Trade off is the rooms are pretty worn out but clean. Service was very good as was food and entertainment.
Video of our trip June 13 to 20th.