Considering all it gets you is an upcharge to be closer to the food court / busses and main pools, I'd say no. But, if the upcharge is nominal, it may be nice to be ground floor and near the pool (I wouldn't do it due to noise at the main pool areas)...
For Sports, especially with a 2 year old who enjoys the water, you may want to actually NOT pay for a preferred rate room and rather request buildings 8 or 9, where the quieter Grand Slam pool is.
However, the Preferred Rooms will get you closer to the Kiddie Pool. But, it's not that far of a walk.
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For Music, the pool isn't as isolated as at Sports, and is a major congregation area (it's on the way to Music Hall instead of off to the side)... Here's that pool.
And the kiddie pool is over by the main "Calyspo" pool, which a preferred room would get you closer to.
So, to me? No, not worth it. But, that also depends on the charge. I've paid for Preferred at Pop before, and wouldn't ever do it again. I'd rather spend my $10 - $20 per night on something else (like souvenirs!).
Have a great trip!