The sprite isles are a good way to take a break from the usual GF experience. The free O-clay is nice. Fishing is something a lot of people who've played other games like to do. So far individualization is dependent on drops from islanders and fishing, but I'm assuming that the farming, ranching, and mining areas will also offer ways to individualize; along with the cash shop, of course.
The amount of exp that you can gain for you isle is pitiful. Fish ten times and get 20xp! Break 5 balls on someone's isle and get from 5-15xp! Repair your isle and get an average of 5xp per hammer! And the fishing, and the balls are once per day. Other people coming to fish at your isle also grants your isle exp, but as no one has done that at my isle; I have no idea how much. 5K exp needed to level your isle! So after you've fished, and broken balls on your full friends list, gone to all your guild-mates isles, then what? If you're like me you walk around Kaslow and go to random people's isles and break balls there. After two full days of doing this, I still have less than 1K isle exp. Am I missing something? Of those (very few considering the number of people whose isle I've visited) who have visited, most are from my guild. And most have only visited once.
God forbid rl should intrude! Go on vacation for a week; be of school age and have to do homework and can't log in for a few days; have to work more than one part time job and can only log in on week ends, and you'll come back to (literally) a smoking ruin of an isle! The rate at which the buildings are damaged is way too high. Even if you do log in every day, it is difficult at best, to keep up unless you're pretty much only doing the isle rpt quests for hammers. And considering the daily divination is dependent on health of your isle, if you want a good one you're forced to grind, grind, grind for hammers.
If you're L80-90 and only doing your dailies and looking to fill time, then the isles are ok. If you're less than that you are going to have a hard time leveling yourself, your isle, and keeping your isle repaired.
The statues: a trophy case to show that you've killed mobs that pretty much everyone else in the game has killed. lol No other benefits that I can find beyond that. Doesn't seem to grant any kind of exp or fame. So no matter how large your trophy case is you still won't even get a mention on the top sprite isle list. And you can collect and display more than one of the same trophy! Hey look, I griefed a L15 area boss repeatedly to gain multiple statues of it! XD