If you do forget it, it's usually possible to reset the system and erase the password. It's often a jumper on the motherboard or as simple as removing the small battery cell that's attached to the motherboard.
I'm not going to try to dissuade you. If I was in your shoes, I'd ask myself, "What do I gain by adding the password?" I'd also ask, "What do I risk by adding the password?"
Those are questions only you can answer. Because it's often a long time between the times where you'll access the BIOS, it's easy to forget that password. That's why I made my initial remark. But, if you're confident that you'll remember it, it's unlikely to cause any harm.
It can also be good if the device is stolen. Once the device is set up, you're already using secure boot, you can go in and disable things like USB booting. That way, if your device is stolen, it's harder for them to access your files (assuming your OS has a strong password) and there's no way for them to install a new OS (without resetting things).