Well, they seem a miracle to me, as only the HO & 1/72 kits much had anything but rubber/vinyl tracks in them (and the rubber ones, like Pyro and LifeLike and some Nitto, were horrible things, vague detail, would dry out and snap, just not good).
So, when L & L started entering the modeling continum it was pretty cool, if a learning curve. No more sticking wires through hulls, or using motor-winding wire around roadwheels, and the like to get sag (and have the track joint fail a couple weeks later 
).
So, the individual links were even better for many applications. Other than the cost of metal ones, that is.
But, I'm ancient, too. I remember when "accessory kit" meant the teeny (like 50x100mm) Heller packet of a tow rope, or 4-6 jerry cans, and that was it. Resin? Photoetch? Nope and Nope, never heard of them.
I'm old enough to remember when Tamiya switched from the "MT" (motorized tank) line to the "MM" (military miniatures) catalog lines. Which meant you had to be sharp, as the M-41 came as both MT-307 and as MM-155 (the later without the four infantry figures, as well as the motor and the like). The MT kits were sized to hold batteries and the like, and were not always to scale height at the engine decks, so the MM series was a major change. And made MRC/Tamiya a bundle in the late 70s, too.
Now, al lthe serious kit makers (seem to at least) offer flexible track in "uses regular glue" format if a person were not keen to build individual links.
I'm also probably the wrong person to ask, since I find setting up deadeyes and ratlines on sailing ships just par for the course. A jig to juggle 7 link parts for M-60 tracks--just part of the process. Getting the "right" tracks for what I'm modeling does appeal to the rivet-counting monster in me, when he gets out of the straight jacket in the closet in the basement where he was locked up.