I would think that a stiff extruded aluminum track through bolted and epoxied into a tight channel would to little to harm the integrity of well constructed table.
A sled that uses the fence as a guide can be damaged if your bit is cutting flush to the table top, sure one can "jig up" to prevent such a cut (been there done that) but a sled that uses a track can be held away from any cutter with any profile at any depth/height within the limits of the entire rig.... I can swing my 3-1/2" raiser at any height and not damage the sled.
I cut my copes with a single pass using a no-blowout backer board screwed to the sled tight to the fence.
I could see a problem if I needed to take shallower bites, creeping up the the final cope but a slotted/bolted backer board could be used in this case for quick adjustments for the multiple cuts whereas a non track sled would just need to be run along the fence at each position.
Aligning the fence to a track sled can be a pain but if you set the backer board to depth of cut then all one needs to do is snug the fence to the backer board at either end and your set. Both my Kreg and Incra setups are set parallel to the slot and do not need to be tweaked any more than my table saw, which also happens to have those "dust collecting" slots.
Clamping feathers anywhere on the table is a non issue, one is not limited to just the track setup, the old feathers and clamps that were used pre-track are still available.
I would bet that most if not all of the manufactured gizmos put out now are based on woodworkers' home made jigs. One can make or buy, a choice. Quite often I'll see a manufactured jig that makes more sense to make, other times it'll make more sense to buy after considering time, materials and effort/ability to make.
Conclusion: if one sees benefit with a track then do it, if one doesn't ....don't.
Not a big deal either way in my book.
One of the coolest things going is figuring out how to do with what you have, all the while knowing that everyone else is doing the same. I have no problem with seeing someone else come up with a better/safer way and incorporating those techniques into to my own. No one knows it all.