As I said before, the data plans in Jamaica as still relatively "cheaper" than that of other carriers (comparing dollar per gigabyte).
For example :If you subscribed to Digicel's 2GB data plan for about ~$1700, you will be able to make more than that ~$1700 in VOIP calls (thus saving yourself credit). Digicel would then be losing potential revenue from you.
I'm sure their next step will be to block tethering on phones so that you can't "sell" or lease internet access to your neighbor