Just be prepared for a lot to change over time. And, each person's situation is different.
How old are the kiddos?
A 3 mile ride might be fine for a 5 year old. And, your beach cruiser would suit riding with the 5 year old just fine.
On the other hand, if the kids get interested in bikes, then by age 15, they may well be ready for 50 mile or longer rides... and you'll be huffing to keep up on your beach cruiser.
But, also realizing that needs change and evolve, there is no reason not to get a bike right for the moment.