Some of your favorite fountain pens have hooded nibs, like the LAMY 2000, but does it serve a purpose? While it can be aesthetically pleasing and allows for incognito fountain pen writing, it's not necessarily the main intention when integrated into a pen design. So what other reasons might there be? Brian tackles this in a previous Q&A:
One reason to go with a hooded nib is the nib doesn't tend to dry out so often. That's because less of the nib is exposed to the outside air. So if you leave your pen sitting out uncapped, it doesn't dry out as quickly. This is a major perk for those using it in a classroom setting that requires quick notes, as you don't have to cap and uncap each and every time. The nib will remain wet and ready to write when the need arises.
Another consideration is it allows the ability to hold your pen closer to the nib. With a standard fountain pen, this would lead to really inky fingers, but with a hooded nib, not so much! While not necessary for everyone's grip, some do push up very close to the nib for comfort and control when writing. The hooded nib allows for this without the worry of ink-covered fingers.
The last purpose of the hooded nib is that the filler hole is much closer to the nib than a traditional fountain pen. So what? Well, that allows for easier filling with low ink levels. You don't have to twist and angle the bottle a specific way like you would do to accommodate a higher filler hole fountain with most other pens. This helps you use nearly every last drop a bottle or sample has to offer!
The Jinhao Shark pen is another example of a pen with a hooded style nib.