Just don't think it's very practical, we don't have to carry cards as much these days thankfully. I just found it a bit weird sorry
Who do you flash your piece of shiny metal to anyways?
Then don't use it.
There are still many, particularly the older generation who prefer using physical cards.
I still carry my physical cards around with me even though I have most of them in my phone, just as a back up and because some hotels, car rental places etc still require physical cards.
Metal cards have a more premium feel and I think it's a nice little package to truly recognise your status, but if you don't want it, just throw it in the draw or bin.
Plenty of places give you things like that, that you don't really need, as people still like some sort of recognition.
Very common from a marketing perspective.
I have my platinum metal bag tag on my carry on bag, has been on there for years and makes it easy to spot my bag in an instant.
Each to their own.
As for the other card for your wallet, I've used that on partner airlines for lounge entry.
For example when I was in Auckland a few days back (flying Air New Zealand), they needed to see the status and member number, I didn't have roaming on, so this was a life saver to get into the lounge quickly and without stuffing about connecting to WiFi when I had a queue of people behind me.