I think this may be the case for our family as well. Growing up near the beach may have overly prepared my children for water more than the average child. However, I will say that my children really loved to just sit in the shallow water and play with the sand.
The two biggest differences are sight lines - at most beaches - even crowded ones, you can keep an eye on your kids - With SAB there are several distinct parts of the pool that are not visible from other parts of the pool - and the lazy river - which is deep with a current - but you might not expect it to be deep if you try and enter there.
My kids grew up on a Minnesota lake - they both had lots of swim lessons from a young age and were pretty strong swimmers because there was a child attractive water hazard in the back yard. But that pool still scares me.