"And" and "as well as" are very similar, but there is a slight difference. For example, if you are talking about your pet dog to someone who doesn't know anything about your dog, you could say "My dog is cute and smart." However, if you are talking to someone who has seen your dog before and already knows that your dog is cute, you could say "My dog is smart as well as cute" to introduce a new characteristic (that he is smart) that the person didn't already know. It's almost like saying "You already know my dog is cute, but did you know he is also smart?" or "My dog is not only cute, he is also smart!" This is a hard thing to explain so hopefully that made sense. Hopefully someone else can explain it better! :) It is a very slight change in nuance.

Example sentence: He is smart as well as handsome. (He is not only handsome, but he is also smart.) "As well as" gives information which is already known by the listener(s). The rest of the sentence gives the listener(s) new information. ~When you say "and" the listener(s) didn't know he was both smart and handsome.