Yeah do what you want. I personally like bar ends, but then I'm old and don't care what other people think, I tend towards..how do you say it... oh, that's right, things that work for me. Personally, going up hill I find them to give me another position and they're worth it for that alone, or when I'm cycling along a low technical trail they give me a break. FWIW I use Profile Stubbies as I quickly found out I didn't need them longer than that. I've never given any thought to leverage, just to comfort and hand position.

Concerning the "hooking trees" argument, I'm sure that happens. But I cycle in woods and I think in 25 years it may have happened once, maybe twice. Given what they give me, that's a fine trade off for me. As for riding in a group and hooking particularly on the average width trails I go on, well I call that complete BS. If you have people riding that close to you, well, I'd be thinking about things other than my bar ends.

Bottom line is do what you like -don't let a bunch of idiots tell you what's cool. Be your own person and figure out what works for you.

Edit: to be fair, that link of the OP does have some incredibly bad products in it -and I did have a shiver of horror of recalling some of the things: elastomer suspension, toe clips, suspension stems, etc