Cyclic is the rating for loads that will regularly occur.
It is best not to go over the 10A cyclic rating printed on the battery for very long or very often.
Standby use is almost for emergencies.
Say the power goes out in a heavy rain storm. The basement is flooding, and the 12VDC sump pump takes 15A.
Do you risk permanent damage to the battery?
Or do you say the heck with the $70 battery, and run the pump to save the furnace, water heater, washer, dryer, furniture, and cardboard boxes of various treasures?
As far as I know, all Sam's Clubs have batteries. You have to be or know a member. And they (everyone) charges a core charge, so take a pair of old batteries with you if you have any. They were $73 each, plus core charge ($8?) last time I was in there.
I am told Costco has 6V golf cart batteries too, and they were a little cheaper.
The golf cart batteries cost about twice as much for a pair (required for 12V use). But the pair has about six times the capacity. Longer service life. Etc.
WallyWorld sells 12V house branded (made by Johnson Control) deep cycles, in ~85 and ~115AH sizes. The 6Vs are still more bang for the buck.
G-