My El Mariachi was my singlespeed, my CAADX is my ‘gravel’ bike, yes you can ride the el mariachi on the road/easy stuff, but the CAADX is more fun and the El Mariachi was for XC/Trail stuff where the CAADX wouldn’t work at all.
My problem/argument was the other way around, I had the EM and then bought a gravel bike which displaced it for a lot of stuff, but not all. Now I have a more ‘trail’ orientated hard tail it’s hard to justify the EM though as the gap between the trail bike and the gravel bike is pretty narrow so it’s* up for sale. If I was to get a new bike now it would be a bigger FS bike, I’ve bought way too many gravel/XC bikes over the years and have just about covered every niche and sub-niche!
*actually it’s not, it’s already been swapped to a Charge Cooker, same niche but less £££ tied up in the frame.