A lead acid battery is destroyed by prolonged periods of low voltage when sulphation occurs.
Let's have a small 44Ah battery with a default charge of 75% ... 33Ah. The camera draws about 0.5A, in 12 hours it draws 6Ah.
33-6= 27 Ah. That's 61% of capacity. If it is driven daily and the charging mode is traditional everything is fine.
The problem is charging a modern car controlled by the car control unit. There it easily happens that even after a long drive you park and the lead acid battery has 12.2 V ... which is 50% of capacity.