People use fancy words all the time. The problem with these fancy words is that they stop conveying meaning or the correct meaning and are used out of context. It is also makes it hard for non-native english speakers to understand. The reason these fancy words are used - is 90% of the time to make the person saying or writing these words look cool or good in their own mind.
Words are to be understood
If your goal is to help others - instead of give them an unnecessary reason to open a dictionary or search a dictionary - then use simple words.
I can understand using words that are fancy in the specific context they were designed for - the domain of understanding.
Orthoganal means independent (or at right angles in the correct context)
The commands are non-orthogonal and when two commands perform the same task they often have inconsistent options or are described with different terminology.
In this instance the author could have written: The commands are not independent.
Opaque means “not see through” - “do not reveal” - “not visible” - “convoluted / not understood”
Metadata is opaque to gRPC itself - it lets the client provide information
In this instance the author could have written: