To cover wood tip or not?

On my potted plants that were supported by bamboo stick, I noticed the bamboo tip were covered with a plastic cover. What is the purpose of them? Asthetic, safety issues or to protect them from rotting?

I recently purchased a trellis made of willow and notice the end were exposed. Do I need to cover them? 

Safety- to stop them poking you in the eye

And no you do not have to cover the willow ends

Thanks Sotongeoff!

I think it would depend. If the ends of willow are anything like bamboo and have small shallow holes it is likely that the caps are put on to stop rain water sitting and creatures getting inside the wood and rotting it. 

Bamboos are usually covered to stop them poking you in the eye. You'll find the same covers on, e.g., clematis sticks.

You can also buy the little rubber ends. Speaking as one who HAS been poked in the eye, I make sure all my home made supports and wigwams have them now.Got mine from Wilkos.

I ll tell you why you need to cover the top of those sticks,I bent down to pick something of a plant which had been staked and the stick went into my eye and caused the most awful pain....I was lucky no lasting damage.cover with a pot to remind you .

I put a blob of white paint on the top ends of bamboos for safety, but love the snail shell idea.

Thanks everyone! I never got poked in the eyes before and don't intend to get one either. Hehe