I'm only going to focus on this part of the question. The rest of it has been covered by @mattnz.
I had always heard that the primary difference with women's bikes is that the top tube is lower to accommodate skirts, and otherwise there isn't really a difference.
You are referring to mixte or step-through frames (link goes to Wikipedia). Those were definitely designed around women wearing skirts. That's no longer true of modern women's performance frames. [Edit: earlier, this post made a comment about step-through or mixte frames no longer being common. This isn't correct.]
Apart from that, this question and its associated answers discuss that in some aspects, modern women's and men's bikes may have some frame differences, and some component differences. Two fundamental properties of every frame are the stack, or how tall it is, and the reach, or how long it is. Hat tip to Bike Radar for this graphic:
As alluded to in the SE post above, many women's frames have shorter reach and higher stack in the same frame size. This may be based in an older paradigm of design, and some manufacturers are committing to unisex frame sizing. They do need to add sizes on the small end, as there's no dispute that women are shorter on average than men and that among shorter people, women are going to outnumber men.
Additionally, women's saddles are designed differently. I'm not as familiar with the design issues there. Women may also have narrower shoulders at the same height as men, which would require narrower handlebars in the same frame size if true.
Out of curiosity, I Googled the men's and women's versions of the bikes. The women's version is indeed designed as a mixte frame. Its top tube isn't dropped as far as others I've seen. I'm not an engineer, but it seems like this design would reduce the lateral stiffness of the bike. In hard efforts (e.g. at least your functional threshold power, or the power you can sustain for about an hour), you might notice the women's frame flexing more side to side. This energy might be wasted and you might be slower on the women's frame. Then again, this doesn't sound like anything that would matter in your use case. It's hard to think of design parameters where the women's frame would put you at a material disadvantage for a 5 mile round trip flat easy commute.
It's not really possible to tell if the other specifications materially differ, because the manufacturer didn't provide enough information. Even the saddles look almost identical! Both of them seem to be one size bikes. It's possible the women's bike will be smaller (i.e. shorter stack and reach than the men's). But the site doesn't provide enough information.
Basically, from what little we can tell on the Internet, there doesn't appear to be a substantive reason not to get the women's version.