General Knowledge of Drenthe

I've been noticing that while the Moes family tree seems centered around the village of Smilde, at least as far as births and deaths go, there is a noticeable trend that baptisms were in Diever about 15km south.
I've assumed that Diever was the closest church to Smilde and hence everyone had to travel for a christening. It seems a reasonable enough assumption but am i missing something?
How big of a surrounding area would the church at Diever have been servicing?
Is there something special about Diever, i would have thought Assen was closer and would also have churches?