I also love that hubski doesn't have much of either element. The community seems to self-select, and the people who stick around are usually pretty amazing individuals!
I'm also loving the site in general, I can use it on Opera Mini without any problem. Reddit is a pain to use on Opera Mini and Voat is impossible.
It is a mobile browser, yes. I personally use it a lot while on mobile data, because it can work in data-saving mode, compressing images a fair amount if you want it to. Also, it has night mode (basically, imagine f.lux, but for a mobile browser), so when I'm browsing the web late I opt for Opera to hurt my eyes less. Other than that, design wise I prefer Safari, it's got nicer animations and transitions. The difference is about the same as between something like Tumblr with a lot of animations/nice graphics and Hubski, which is rather minimalistic.
I also use it while on mobile data because my data cap per day is 10Mb.