I did not buy or employ bar-end shifters until a month or two ago, as I either worked indexed down tube shifters or STIs/Ergos. Since many of my bikes were race bikes, I wanted them to look like race bikes and to shift them like they would have been. STIs/Ergos also fit the bill as it allowed even faster shifting etc etc. Bar-end shifters were, to me, something for touring bikes, which I was not super interested in for a long time. Add to that, when getting out of the saddle to accelerate (fun!) or to climb hills (less fun), I feared ramming my kneecaps into these pointy things and having a lose-lose scenario of gear selection disaster AND injured knees. So I took a hard pass on that stuff until very recently. I found a killer deal on Dura-Ace 10s bar-end shifters and hooked them up to my evolving-winter-rider '74 Paramount, for which I had also found paint-matching matte black fenders for. As the Paramount is a P15 Touring model that would now be in service during the demanding rain/cold months, a dignified ride, ridden in a dignified manner (not racing, out of the saddle shenanigans, but in saddle 99% of the time), deserved a dignified (but updated!) C&V shifting method. Voila, bar-end shifters.
If I'm going to be hunkered down, moving quickly, DT shifters or STIs/Ergos are the way. If I'm going to be going slower, taking it easier and looking around, and am set up more upright for comfort, DTs are out and bar-ends are in. I really enjoy it now, and with the brake lever grip being perfect thanks to Cinelli Criterium bars, my hand elevation drop from hood to shifter is minimal and intuitive. To the point of grabbing air with my hand when I briefly rode a DT shifter bike!
So I think, if you know your riding style, type of bike, and how animated you get when climbing/accelerating out of the saddle (to say nothing of bar height and thus shifter height), and you know that shift cables won't get in the way of a front bag or rack, go for it. I'm always conscious of where my knees are when out of the saddle on the Paramount, which has helped me avoid getting stabbed (though I've brushed the levers a few times).