You're making the assumption that the intelligence apparatus of foreign countries is some purely rational actor. You can bet they are doing something of value, but that doesn't make the bet correct.

For all we know, China may have decided that every Baptist church is a possible nuclear launch site and that they all need to be priority #1 for surveillance. Particularly on Wednesday nights when all the folks in the surrounding community come in early in the evening and sometimes don't leave until late at night.