Because, like nearly all rep/aftermarket watch-related components, they are used/unserviced & put together (by non-watchmakers) in peoples' homes, on the streets, in alleys or wherever the 'factory' is located, & there is little or no QC.
If there is a 7750 inside, yes.
By the way, I do not think the dial is bad at all. But the subdials on most non-Newman aftermarket dials are slightly too large, which is their principal give-away.
But they do vary. I cannot point you to any specific dials or sellers, but some dials do have more accurately sized subdials. You just have to look around.
2nd after that is the glossy appearance of the subdials (the gen dials are completely matte).
Most people want to replace the missing paint in their bezels. But if you really want to remove it, just use mineral spirits or a rag moistened (not dripping wet) with paint remover.
Either way, as you wear the watch, the paint will wear away naturally all by itself, which always looks more natural than removing it artificially.
I would not touch the bezel, but the case could use a bit of work to give it that 'naturally' worn look.
Gen xtal is always nice (the beveled versions give the Daytona a nice, jewel-like quality), but it is a relatively high cost item that offers relatively little in return since many gens have aftermarket xtals. I would also consider a gen bracelet (62xx Daytonas on straps never look as good to me as they do on gen bracelets) &/or a better dial (subdials a bit too close to markers vs gen dial).
Reps are notorious for having poor quality crowns & crown tubes, which results in misthreading..........often within days or hours after delivery.
The options are to replace both with gen parts (crowns can be found on ebay & the for sale sections of gen Rolex sites) & gen or Swiss-made (functionally the same as gen) tubes can be found at most watchmaker supply sites. Depending on the particular rep watch case you hold in your hand, the threads in your case may need to be retapped in order to fit either a gen/Swiss-made or another rep tube. Unfortunately, due to the lack of QC & construction variability of rep cases, the only way to know if your case requires retapping is to try to fit another tube. I am not aware of any shortcuts to this.