I didn't realise until I actually listened to it but this is pretty well what is still the format in the "Wee Free" church here in Scotland. Some would describe their outlook as "narrow" but they don't use diabolical musical instruments just this unaccompanied singing. In places like Lewis they still keep the old customs such as not using money or doing any form of work or recreation on the Sabbath and they still don't allow the ferries to run on that day. Buses run but the driver will not take money for the fare - it is left in a dish to be collected the following day. There hasn't been a cinema there for years since it had to close after showing films on a Sunday but, strangely enough, there are some hotels that open and sell alcohol on a Sunday.