I believe it depends on the perceived value the owner assigns to the cue, and that's all.
Even a very trashed cue butt might be able to be used as a blank for a new cue. At that point you are not repairing or refinishing but supplying a blank. And frankly it's possible it can provide a nice blank for cheaper than you can buy one. It depends...and only a CM with the cue in his hands can tell you if it is a reasonable endeavor.
If you really like the cue and all it needs is a shaft....get a shaft. That's what I think.
This is not uncommon in general outside of cues. Look how many people dump money into a car or bike that could never be recovered if it were sold. Heck, I have done that myself.....lots.
I remember a lot of years ago dumping money into a car that my brother said wasn't worth it. A lot of people told me it wasn't worth it. Just a beat up old Ford with loud exhaust and a big V8. That Ford was a Shelby. It's gone, but at least I can say I had a very hot affair with a very hot car that many only dream of owning. I didn't care that it was a money pit at the time.
If you like it, fix it and enjoy it. You only get to live this life once. Only an sneaky? Hell many cues with a TS on them are "only" sneaky petes.....
If you dig the cue you could have a full splice cue with a custom shaft for relatively little money, just get a shaft made.....that's a serious billiard instrument....or you could use it to prop a window.
