The advantage over ps?
- Showing off
. In fact I think that's about 25-50% of the dslr users.
I think you covered the serious side so let's see the funny side..
It's amazing how many guys buy a camera just for that. Especially in developed countries men in that range have more $$ then skills or desire to learn.
They get their 1st cam (min a 5d3 to start with) in their 30s-40s and after a month they give advice on forums
or they get a Rebel and next week they ask how much should they charge after becoming a wedding photog overnight...
I have a little view on that due to the stories I hear from the gallery/frame shop, the local printing places I'm in business with and the models I worked with.. I.e. there are plenty pervs on MM who only registered to snap some photos with pretty girls in a bikini (or nothing). The last guy told my GF he has 30+ yrs of experience and his photos suck on multi levels... and let's not talk about local wedding photogs...
Anyhow, a 7D can make great images, (heck, most recent cameras can) it can even do family/vacation photos, yet some people are "convinced" they can only do that with a 1Dx or at least with a 5d3 and L glass only.
Then they snap shots that are never printed larger than 8x10 and could be easily done with an entry dslr, a m4/3 or with a ps.
It's probably related to midlife crisis too.
It's cheaper than a red/yellow Porsche and easier to sell when it's over. It's also easier to "explain" to the wife.. or maybe it's just marketing.. like: you have to have an SUV or you're not a good/safe parent, you have to use this detergent, baby/dog/cat food.. etc.. or you are not a good... etc...