Agreed [emoji106]
BMW has a section on AGM I believe...newtis?

The constantly increasing energy demand of modern vehicle electrical systems calls for ever more powerful battery solutions. A modern luxury-class vehicle has some 100*actuator motors that have to be fed with electrical current. Added to these are safety, environmental and comfort elements which are increasingly becoming standard features, such as e.g. Antilock Brake System (ABS), Dynamic Stability Control (DSC), steering assistance (EPS), electronic chassis and suspension control, air conditioning and navigation system. Current consumption is considerable even when the vehicle is not in use.

The somewhat higher price compared with a battery of similar size is fully balanced by the following benefits:

greatly longer service life

improved starting reliability at low temperatures

Safe starting of engines with high starting power requirements, for example high-performance diesel engines

100*% freedom from maintenance

low risk in the event of an accident (reduced environmental risk)

They list more benefits...

Construction

The AGM battery differs from the conventional lead calcium battery as follows:

larger plates: Larger plates allow a 25% larger power density.
Separators made of glass-fibre fleece: These can cause an up to 3-times higher cycle stability to be reached. This improves the cold starting capability, the power consumption and service life.
Airtight housing with pressure relief valve (please refer to ”How it works”):

The inspection plugs are sealed and can not be opened.

Battery acid bound in glass-fibre fleece: Battery acid is not found free in the housing as before, but is rather bound 100% in the glass-fibre fleece. This gives increased security against the acid escaping and thus reduces the environmental risk.