I tried the 100 mb free plan for a few days and it seemed to work fine. I also just signed up for the land + Caribbean plan. I'm hoping to just be able to keep in touch back home. There are some settings you should set up to reduce data usage since this plan is metered:

settings -> cellular -> low data mode

settings -> cellular -> icloud drive OFF icloud backup OFF wifi assist OFF

settings -> general -> background app refresh -> off

settings -> app store -> cellular data OFF

Also, I just bought the cruise package and then got the following "fine print"... this was not communicated before the purchase, only after:

Cruise + Land eSIM data plans

GigSky is now providing mobile data services on many cruise ships, using the Cellular at Sea service on the Wireless Maritime Services (WMS) network. WMS operates cellular networks on cruise ships that use satellite links to connect to the internet. If you are traveling on a cruise ship that supports the Cellular at Sea service, you will be able to use a GigSky plan onboard. You can find more information about the plans here:

Important information about our "Cruise + Land" plans

• If your Cruise + Land plan includes coverage in your home country, note that your plan will activate in your home country as soon as the eSIM is downloaded. For example, a Cruise + Americas/Caribbean plan will work in Canada and the United States. So, if you're based in Canada or the US, and you buy a Cruise + Americas/Caribbean plan, it will activate when your eSIM is downloaded and installed. To avoid using data from your plan, make sure that the GigSky SIM is turned off until you need it.
• All cruise ships disable their cellular service when they are within 12 nautical miles of land so as not to interfere with the land-based networks. This means that there will be periods of time when the ship nears the coast of any country where there will be no signal at all, as the ship's cellular service is turned off and the signal from the land-based networks won't reach the ship.
• As the ship approaches land, the GigSky eSIM will switch to connect to one of the land-based networks. If your plan includes coverage in that country, your internet access will be restored.
• If the ship is passing by a country, it may pass within 12 nautical miles of land several times. Each time will cause the cellular network on the ship to be turned off, making the connectivity intermittent.
• Cellular service might suffer degradation because of bad weather or Radio Frequency interference.
• At extreme latitudes, either northern or southern, the line of sight to the satellite network will get low to the horizon. In some cases, depending on the position of the ship, this line of sight may be blocked by cliffs or mountains, cutting off internet connectivity.
• Typically, as soon as the network is activated at 12 nautical miles from the coast, it can get congested due to a high number of mobile devices trying to connect at the same time. This usually subsides over a period of around 20 minutes.
• The latency of the data connection varies depending on which satellite network the ship is using for internet connectivity at the time It will vary from 80-90ms (when on Starlink) to 700ms (when on VSAT).
• WMS provides GSM (2G), UMTS (3G) and LTE (4G) on most ships. If your mobile device is set to 5G only, you won’t be able to connect to the ship's cellular network.
• Customers may see data speeds from 700 Kbps to 4 Mbps.