Of course modifying stock engine to a monster is waste of money, if u compare with transplant. Why some peole are willing to go to such extent instead of just swapping engine and live happily ever after? Some people play with stock engine coz personal preference, some people are afraid of transplant (reesale value drop, fear of JPJ, fear of being cheated, fear of getting blown 2nd hand 16-years old halfut etc etc), some find it's alot more satisfying to mod stock engine to a monster.
Drivability is different among different drivers. Some drivers always play with hi-RPM so weak bottom-end is OK with them. Other drivers prefer strong mid-range torque.
I won't stay with carb for long, I'll go for EFI in future. No matter how cheap carb is, no matter how troublesome EFI can be, carb can never beat EFI in term of precise & smooth fuel delivery.