I would bet that you think I am going to say that the benefit of playing a musical instrument such as the piano is that it increases your temporal-spatial ability or your math skills.
Maybe you feel it will increase your focus and your memory and will challenge your brain.
These are all true but they are not the primary benefits of playing the piano.
As a teacher and performer, I will say that the benefit lies mostly in the creation of beauty.
I know, this sounds so cerebral but it is true.
Music enables us to express our emotions through tones and rhythms in a way that no other language can.
It allows us to express our true selves and in the process, see amazing beauty.
Whether you are playing a Chopin Prelude, a Gershwin melody or a Stevie Wonder song, music moves, enlightens and releases the soul.
And this is the best and only reason that we need it in our lives.
By studying and learning chords, we can learn how to play just about any song out there.
And by understanding the chords of a song, we understand the harmonic structure.
Then we can play our favorite songs and even play them in our own way.
We create our own arrangements and this is very beneficial.
We listen more, become discriminating and develop our internal and creative minds (and ears).
So is playing the piano beneficial? Take my word for it and try it out.
You are never too old.