Hi Tatertot!
It seems to me that general facts don't matter much here. Your pool builder has said he doesn't like doing them. That means to me that he is limited somehow--not enough experience or his crew can't be trusted to do the job correctly in a concrete apron, or he's had problems in the past and doesn't know where in the process he failed. It doesn't matter whether I or the next TFP member here has had fabulous experiences with their deck jets. YOUR builder is steering you away from them for a/his reason. Do you know what I mean? I would be leery of asking a contractor of any kind to do something that isn't his forte.
Now, I could have totally misunderstood what you wrote.
Will you be having any other water features installed? As Dave said, deck jets or a waterfall can cool the water. Should you ever choose to have a salt water chlorine generator, the deck jets would be helpful to raise pH after lowering total alkalinity--a part of life with SWCGs.
Deck jets are fun for the kids to play in or around. For the adults, they can provide that nice running water sound--they can also be quite loud if you push a lot of water through them and live in a quiet neighborhood with your neighbors nearby. They are soothing to look at. FWIW, our surround is pavers. Our builder drilled holes in the paver stones to accommodate the spitters.
Maybe you can dig a little deeper with your builder and find out more about his concerns.
Good luck~~
Lana