I agree that some modern lines have really kinda made me lose interest in getting super creative with stupid deep line setups. It's quite easy to get a Big Game Depthfinder or equivalent down to 30' or more.
At least in regards to Tuna that's plenty for me. There are probably times when getting deeper quicker could be helpful, but for me anyway I'm just not super interested in sitting there deep soaking lines for fish that don't want to come up. I'm just not going to spend time doing it and would rather go find fish that want to come up and play. Of course I'm also running a charter so I can't exactly justify spending a bunch of time not catching fish. If I was just out there fishing for fun I may dedicate more time to it. One of the biggest factors with albacore fishing is that its expensive and you only have so much time out there. Whether on a charter or on your own, it's a lot of financial investment which makes it harder to justify experimenting a ton. There is definitely a time and place for super deep out there, but I just find one of the fast sinking integrated heads is plenty for my needs 99% of the time. I think I just lack the patience needed to really sit there and soak flies as deep as possible. I'd rather just get up and go looking for fish that want to play shallower.
There is no doubt a T17 or T20 head will get down deeper than those other lines, and it's certainly not a bad thing to have such a setup available. Especially if you're willing to spend time deep soaking. I've seen a lot of people soak flies deep while we are stopped and waiting while someone plays a troll fish, and I've seen this produce some fish here and there. What I haven't seen yet is a situation where getting super deep was the difference between getting a few fish in a day and really loading up, though no doubt that's partially explained by my lack of serious time dedicated to it. I think as the years have gone on my experience has just lead me to believe that I'm better off continuing to look for opportunities where I can get the fish up and going shallower rather than sit on fish that are 80' down and not coming up any shallower. The other aspect is that these modern lines are just sooooooo much nicer to cast. They really do cast exceptionally well. So while it certainly wouldn't hurt anything to have a stupid deep setup rigged and fished all day, as you don't HAVE to soak it deep if the fish are up and going hard, casting those lines is a whole different animal and something I don't particularly enjoy if I don't really have to.
I often wish albacore fishing was like other fisheries where one could just drive to the water and experiment without a big financial investment. Maybe next year I'll play around with more of this while I'm casting flies while on bait stops. Doesn't cost me anything to be out there so I have the advantage of being able to experiment more whenever I like.
For bottom fish, however, the faster/deeper the better IMO so such setups definitely still have a place. I've always had an interest in using one of these lines to try for chinook in the ocean as well, though I haven't done it much. Last year we never really saw it as the fish tended to stay out in 300-450' of water, but many years we have good chinook fishing close to the beach in 30-100' of water and I've always wanted to spend time casting flies with super fast sinking lines to see if I could get some kings. That would be a ton of fun.
