Don't get beach cruisers like those. Personal opinion, but you asked for opinions.
Even on flat ground they weigh a lot (and I mean a lot), they are tiring to push down the road. Is it bad ass and going to get you in shape? Maybe, or it could hurt your knees and make you think of biking as too much work to bother with.
While you may not be contending with hills, wind can be every bit as bad or worse. The ability to change gears, especially when towing a trailer, is very nice to have.
Also, those particular bikes lack real brakes. They have a coaster break in the rear wheel, but a rear brake can only provide 40% of your total stopping power. Not an issue on a leisurely stroll, but a big issue if you need to stop in a hurry (ie in traffic) while pulling a trailer.
Some (very biased) people call bikes "the most efficient machines ever made"; this is only true when you ride a bike designed with efficiency and practicality in mind - as the vast majority of bikes available from a local bike shop are. Beach Cruisers, in my experience, are almost entirely designed for "the look", and just like their motorcycle counter-parts the Choppers (ie Orange County Choppers), lack any semblance of practicalilty. I will also add in, that most bikes built and sold for bike box stores don't have efficiency as a design criteria. Their sole criterias are "inexpensive to manufacture" and "easy to sell quickly". The first means that durability, dependablity, and rideablilty are all sacrificed at the alter of 'cheap to make', and they tend to make a passing visual resemblance of what is currently happening in the higher end bike world (to fool people into thinking they are getting something better than they are).
Keep an eye out for an old mountain bike or hybrid in your size, plenty show up on craigslist for under $100.
My 2 cents,
Matt