I personally am fascinated by the names of fictional characters because they are usually given to help mirror the character's personality or some how give an illustration of them. What is unique about writing about a character of a foreign descent is that there are usually variations in the given name of the character.
Giovanni's original Japanese name is Sakaki. This name might confuse the English speaking audience as we might not be very fluent in the names of Japanese Culture. Sakaki is actually an evergreen tree that blossoms in warm areas of Japan, China, and Korea. What is also interesting about Sakaki is that it is used in sacred Shinto rituals and its kanji together is written containing the kanji for ki meaning “tree, wood” and kami meaning “spirit, god”. The name given, however, is most likely due to the fact that the Earth Badge was designed to represent the Sakaki plant. One could speculate that Sakaki [Giovanni] himself is in a place of great power and could play the role of one who may be treated as a “god”. The Earth Badge is also a representation of Higher Power. When the trainer receives the Earth Badge they are able to train Pokemon of all levels and these Pokemon will listen to their every command without question.
The name "Giovanni", according to Baby Hold is of Hebrew descent and means "God is Gracious" or "God has Shown Favor". Honestly, it would be a long stretch to say that these meanings are why the company chose to dub him Giovanni. God may have shown him favor with wealth and fortune, though his exploits are definitely evil, and what goes around comes around. I speculate that Giovanni's name is in reference to the following:
Giovanni's appearance is that of a Yakuza/Mob Boss. These men are in positions of high power and are very shadowy figures. Because of this representation Giovanni was given this name, typically given to Italian boys, to illustrate his power as a Mob leader. My second point references that of a lingual pun. Giovanni's Pokemon are all ground-types and "Geo" means Earth. So by combining both of these concepts, it would seem reasonable that he was dubbed as such. Personally, I like the name Giovanni, I feel that it fits him in a way that I cannot really describe. Maybe it is because I grew up knowing him that way or because the name sounds like an old, Italian Man? Either way, his name(s) show his status of high power and prove that he is an individual to be reckoned with.