Why is calligraphy considered to be an art in Japan?

Question:

It may sound ridiculous but it looks so simple to write characters and yet one has to study a lot to do that?

Answer:

Because kanji are ideogram, not a phonogram as English alphabet.
Every single kanji has its own meaning(s).
Everything that has a meaning in this world has a life and its own spirit, right?
Calligraphy is an art to visually emerge their lives and their spirits on the plain sheet of paper.
You may like a poem in English. But, only way you can appreciate it is to either read it in a book or listen to the poet's own reading (if you have a chance), but the poem itself would never been visualized (except for in your mind and imagination).
But calligraphy can visually show you the living spirits of the words on the paper. Not to mention, everyone writes his/her own way; but all of their calligraphies (from elementary school children to our grandparents, not to mention, professional calligraphers) are alive and kicking. If this is not an art, what is art?