My bit of nostalgia...
I was a AU on my Mom's Plat card from the time I was 18 and had my generic card shortly thereafter, Old Blue! I became a primary Plat cardholder when I was ~26. Amex has gone to bat for me in purchase protections and been way easier to deal with than others with insurance and item protection issues. I tried calling Citi today about something that should have been processed 2 weeks ago and got transferred to a dead phone line.
Now don't get me wrong I optimize where I can and hold premium products with both Chase and Citi as well, but Amex is OG, and quite frankly provides benefits that the others can't or choose to not replicate. Nearly all of my organic spend goes on Amex cards, with the exception of rental cars which goes on a Chase card because Amex annoyingly doesn't provide primary coverage. Chase however has cards that are incredibly easy to MS and UR are a valuable currency as well, so most of my Chase spend is MS.