They're not good datapacks they're just "OHOHOH GUESS F*CKIN WHAT MY MAN minECraft bUT FRICKin dirT DRops enD CiTy loOt!!!!1!!" that shit is just the result of children being easily entertained, datapacks with effort hardly get any attention. Look at Florcraft, The Creeper's Code, Ordana's Inferno, Mechanization, Accessory Bag, they're amazing, they're works of art but hardly get attention, those are datapacks but they don't get popular quick because they don't entertain children.
The two should not be compared. They are entirely different. Minecraft is more about the creation side of a sandbox, and Terraria is more about the discovery. The only similarities are the fact that you exist in a pixel art styled world, that allows exploration and creation.
There was this website, called "Sploder." Not sure if it still exists... And with that website, you could create games and share them easily. While playing online, I found a lot of games based on this one game called "Minecraft." I told my parents about it, got Minecraft PE, and never stopped playing. I started playing Java about 3 months later, and it's what I play still now.
I think that the Beacon is a good enough use. In my mod, I have it an alternate use to make weapons, but I've changed a lot and now will say that making it a choice between a Beacon and something equally as awesome would be really hard.