This is an example of playing off the risk of assuming the filed type is correct versus the potential for frequency congestion and some mild controller/pilot RT irritation.
The much greater risk is that the filed type is incorrect, and the safety implications this would result in. There's lots of ways we could cut down on RT time but the efficiency gain on the RT would be negligible compared to the safety benefit we'd surrender.
In an ideal world all filed plans would be correct, but some aren't and therefore currently the most robust and also the cheapest way is to get you to report it on the RT. If the RT congestion is so bad the controller should split the sector to relieve the pressure.
Type changes are passed onto the tower so they can ensure their conditional clearances are accurate, and I think some stands can't take certain types? Maybe someone who can see planes at their place of work can answer that one.