Abilities not used are abilities wasted. That is, when you have the capability to achieve something worthwhile, yet choose not to, no purpose is served, an opportunity is wasted.

Of course every action, our entire behaviour throughout life does not have to be purpose focused; however, not being all you can be does seem to be a misuse of your time on earth.

For Your Pleasure

Having a feeling of happy satisfaction and enjoyment is subjective to an extent.  Recognizing variations to the magnitude of impact,  when some activity is considered pleasurable it would probably be considered pleasurable by others as well.

In general, things that create pleasure for one person often generate similar feelings for others.   Accomplishment and satisfaction are generally pleasurable to all.

By inference, using your capabilities to the max, rather than letting them be idle, will lead to accomplishment, satisfaction, and pleasure.  It is worth extending yourself.

Missed Opportunity

If you don’t try using your ability when the opportunity presents itself you may not get another chance.  If you don’t leverage your abilities to the maximum when you can, you might lose the ability to do so (use it or lose it)

A word of caution though,  stretching your abilities beyond your known capability is not recommended.  This could be painful and have negative consequences.

However, when you have the ability to try with a reasonable expectation of success to not do so is a waste.  Don’t be wasteful, go for it.