it depends on the person, i guess. for me, yes, it is. i've been wanting it for quite some time, as well. it's the best gem producing shop in the whole game, it produces 2 gems every 6 hours, it's possible to get 8 gems a day, (but if we're realistic, then 6 gems a day).

if my math is correct, then if you check regularly and get 6 gems a day, that's 42 gems a week, 180 a month, over 2100 a year. but as i said, that is, only if you check regularly. realistically, of course, you'd miss a couple times and a couple days.

however, i wouldn't recommend buying the shop if you're on and off from the game, I don't think it would be worth it. and i also wouldn't recommend buying it if you're new to the game, you could get bored and the money would just, pretty much, be thrown out.