Denti:
Granted, it looks very precise, especially if you have the same indication as on any precision approach (ILS/GLS), which is the standard on 737s now. However you have to be aware about the pressure and temperature effects on FMC derived glidepath indication. Something that PAPIs do not suffer from.
No doubt that temperature affects Baro VNAV (except for the compensated systems). But, if Baro VNAV is the only IAP certified glidepath option, it is a whole lot better than no vertical path. And, becoming visual at typical minimums its errors are minimal and its better to stay with its stable path than attempting to transition to a VGSI.
Finally, Baro VNAV systems in RNP AR qualified aircraft have to perform to some very tight requirements.