More detailed is not more accurate
A 3km model shows much finer detail and will enable more accurate region and locality forecasts
While the new setup might indeed be able to provide more accurate forecasts, it's not a given; it could continue to be wrong just in higher definition.
My understanding is that the biggest deficit for forecasting is the lack of sensors, hence, the various ideas to use mobile devices and networks to gather more data. If this is the case, then can we have our forecasts without ads, as we're obviously adding value collecting all that data, which can then be sold at a profit to farmers, governments and spooks.