Let's just be clear about one thing. All your various comments that included statements that boiled down to "it's not worth it" are totally subjective and are read (by me, anyway) as "not worth it TO YOU."
The investment in the training and equipment is totally worth it to many folks, even if you don't take advantage to use ALL the capabilities available to you once you've done it. You don't have to dive deeper or longer to appreciate what you get out of basic technical training.
Personally, taking Advanced Nitrox and Decompression Procedures was a pretty good investment for me, in time and money. But, it was the BEST THING I ever did for my Recreational/Sport/NDL diving. It totally freed me from the pressure of The Wall (i.e. an NDL). I used to always feel pressure (from myself) to maximize every dive. I.e. get the most bottom time possible. That was because I had the limit of the NDL, which I would not exceed (until I had the right training). Since I had that wall, I wanted to take advantage and use every minute right up to it.
Once I was trained for deco, that wall and the pressure I put on myself because of it, was gone. My recreational NDL diving is SO much more relaxing and stress-free for me now - because I can look at NDLs as simply an advisory, instead of a limit.
Plus, once I got the basic equipment (i.e. doubles and the related reg set), I started using that pretty much all the time - even for shallow, recreational shore dives. All that surplus gas plus the redundancy of the regulator setup is like my security blanket now. All of it together makes my diving so much more "relaxed" and low-stress now. Not that it wasn't fun and relaxing and low-stress before. Now, it's just even better. Now, I don't sweat trying to squeeze out every minute of bottom time that I can. I enjoy the dive for what it is and come up when I feel like it. If I still have NDL left, no big deal. If I got a few minutes into deco, also no big deal.
Bottom line: I feel like I am a better and safer diver, even on NDL dives, since I got tech training. That made it worth it, to me.