Is it possible to be smart and knowledgeable but still be considered ignorant from a spiritual perspective? What does chapter 50 say?

Yes, absolutely. Chapter 50 makes a clear distinction between worldly knowledge and spiritual wisdom. It warns that a person's knowledge is essentially ignorance if they are without devotion. This applies to someone, even if they are considered 'wise,' whose mind is constantly fixed on acquiring wealth and luxury, who is unsatisfied in sense enjoyment, and who is always preoccupied with their wife and children. According to this chapter, such a person, being deluded by these attachments, does not know their own true welfare and is thus living in ignorance.