I'm not saying the resort doesn't need more than just this, I'm just saying that if they had to pick one thing, then this was the right pick. There's been massive lines to the water fountains this past few weeks because of the heat. The resort needs rides that can cool guests off.
In regards to the placement, I mean... with the way the park is laid out, it's not like it could've really gone anywhere else except around the lake. The only other option would've been to ship it over to the other park (and even then the only logical placement there is the empty area next to Pirates, another boat ride).