Not having at least a main fuse in your circuit is just lazy design. With batteries the size we use, safety should be a top priority and although a fuse in this position won’t protect the battery from all situations, it still helps.
Ideally, if you’re building your own battery, you should be fusing each cell separately.
There’s already been several instances of people’s boards going up in flames on these forums from various types of short circuits etc, even when using the standard design that the space cell uses. Something that I don’t use anymore
Yes you are correct, it is wise to use one. I am mistaken. Some antispark switches have fuses integrated or have options to do so as well. We should be using fuses.