Do pipettes always outclass glass syringes?
Glass syringes and glass pipettes are high precision and high accuracy tools of an analytical chemist. Like any tool at home, such as a cloth cutting scissor and a plant pruning clipper do the same job of cutting but their applications are different.
As an analytical chemist, I have not seen anyone using microsyringes for standard preparations in volumetric flasks. One uses a class A pipette for volumetric transfers and to make different standards.
Now you wish inject known microliter or nanoliter volumes in a GC injection port or an HPLC rheodyne, can we use glass pipettes? You would choose a glass syringe to pierce the GC septum.
The tip is that you would use the highest quality glass pipette (class A) and highest quality syringes in each case. class A 1 mL pipettes are commercially available.
If you really wish to compare, you would have to do a calibration yourself on a analytical balance under tightly controlled conditions.