Due to the fact that the audience of this question is comprised of individuals visiting a philosophy website, I can assume that the concept of introversion(within reason) will be met rather conciliatorily. However, when reading Nietzsche's work, it is hard to say whether we should take his words concerning isolationism to heart.
"One must avoid chance and outside stimuli as much as possible; a kind of walling oneself in belongs among the foremost instinctive precautions of spiritual pregnancy".
"I go into solitude so as not to drink out of everybody's cistern. When I am among the many I live as the many do, and I do not think I really think. After a time it always seems as if they want to banish my self from myself and rob me of my soul".
It appears here, as in much of his writing, that Nietzsche almost romanticizes the idea of complete isolation, and has few fine sentiments concerning social interactions.
"The most common lie is that which one lies to himself; lying to others is relatively an exception."
"Perhaps I know best why it is man alone who laughs; he alone suffers so deeply that he had to invent laughter."
Here, it appears as though Nietzsche admits to fabricating thoughts in order to spin a protective cocoon around his own psyche.
I admire Nietzsche a great deal, and want to apply his sagacious teachings to my own life. Nevertheless, it is well known that Nietzsche suffered from many societal wounds during his life time (with mentors, as well as romantic interests), so I am not sure if I can trust his bolstering of a reclusive lifestyle.
I do not question whether introversion is better than extroversion. Clearly, many brilliant people thrive around others, and come up with very important ideas. Contrarily, copious geniuses were only able to come up with their ideas by isolating themselves completely.
Rather, I question whether we can trust that Nietzsche really believed that this was the best way to live, and if we can take his ideas concerning the matter to heart. It seems possible that he desired social interactions, but was simply met with rejection (and subsequently formed a protective shell around his psyche to stay in denial).