Dentists routinely recommended the more-expensive ceramic teeth replacements for teeth in the back, even though ceramic is less durable than the metal counterparts. Even though you basically can never see the hind teeth, so cosmetic reasons shouldn't have applied as they do for front teeth.
I notice metal in peoples hind teeth all the time. This is still a cosmetic need.
Food for thought. If teeth are constantly grinding against each other, is it good for the opposing teeth to constantly be grinding against a hard material like metal?
Choosing the correct tradeoff between cost, appearance and durability is a value judgment. While the importance of appearance is lesser for the rear teeth, I wouldn't write it off entirely.
Why not have a specialist collect the data needed: pictures, temperatures, blood pressures, basic answers to questions, etc...
Then farm this data out to several doctors who make a diagnosis -- until you've reached a statistical significance.
Then, use this data to train a machine learning model.