Hi Ian,
Because 'reconnaissance' is gratitude rather than appreciation which was the term used in English.
The term bien aimé ( noun) sounds a bit preachy and literary to me.
I would use it as an adjective but not as a noun.
Ma robe bien-aimée = my cherished/favourite dress
Please take a look at the following page with lots of useful examples -
https://www.larousse.fr/dictionnaires/francais/bien-aim%C3%A9/9154
Hope this helps!
