Why not glue up as a one piece? Easy, strong and how often do you really need two piece?

In a smaller vehicle, a one-piece can be awkward to stow, and strapping it to the roof rack isn't very theft-proof.
Also, a one-piece can't be stowed easily on deck as a spare paddle.
When on camping trips, a two-piece can be stowed overnight in most (longer) cockpits,under the cockpit cover, so one less item to blow away or get stepped on.
Two-piece paddles with straight shafts and simple ferrules can be shortened (depending on the length of the round shaft section), so some otherwise excellent paddles from the era when 220-240 cm paddles were the norm, can be put to use again.
So there are plenty of advantages with the 2 piece, 3-piece (like some carbon Greenlands) or even 4-piece (like some Lendal) paddles.

Balanced against that is the much greater strength of the one-piece, the lack of hassles with jammed paddle sections, lighter weight with no ferrule (though the ferrule doesn't affect the swing 'weight'), etc. .
I certainly would convert a paddle to a one-piece if I thought it was necessary.
Werner will do some repairs but with shipping costs added in, the economics of repair vs replacement need to be balanced. A friend recently had a new Cyprus with a snapped blade (accidentally jammed between rocks by a beginner friend). Werner is replacing the blade but it's going to cost about $400 CAD total. The cost of replacement is quite a lot more than that.