If a group 27 battery somehow could fit my 2-volt cell plates it would be a 6 volt battery with about 40 amp hours and the battery would be HEAVY!
It's a trade-off.
Performance for longevity. But some folks are infrequent users, taxing their batteries but lightly. They do not need really thick plate batteries.
This is what causes all the confusion. If an owner is "convinced" his way is "best" then they may make a big mistake and insist "Their Way Is The Only Way" to others. They remain adamant. And eager listeners (readers) get an overdose of hyperbole that has little in common with reality.