Sanskrit calligraphy is a direct way of invoking energies and realities. Words are powerful. Uttering them is one way of invoking these realities.
Mantras (sanskrit formulas) have been used as invocations for thousands of years. These mantras are sung in the form of bhajans and khirtans (two forms of singing). They are used as well for meditation.
Writing calligraphies works in the same way. For instance when you write the word:
this is the quality you invoke in and around you.