Attaching a fuse to a new set of batteries?

Due to various craziness in life, I let the batteries on my rig expire, so the only purpose they have is a core charge refund. This time around, I'm getting two 12 volt jars, using 36" 0 gauge cables with ring connectors to connect them in parallel, and fuse block with this fuse for it. The fuse will go on the positive side of the bank.

Other than going with 12 volt batteries, are there any downsides to fusing the battery bank with a 300 amp fuse? I can't think of any, and I'm doing this, mainly as catastrophic protection in case of a short.