fdisk, on the other hand, was a thing in the DOS/Windows world, too, back in the day, and dealing with partitioning is something you are going to do regardless of the OS you are using.
How do you write disk images (like, if you're installing a new machine and you need to write the installer to a USB drive)? I always use lsblk to find the right device name, then dd to write it.
I just make sure I point at the right device letter.
For all it worth in the last 10 years I never need to bother with it, because in the worst case I write the installer in Windows environment and when I install it on the machine (be it a hardware or a virtual machine) it doesn't matter.
inxi is a new one for me.
Command usage / knowledge depends on what you need and why.
For me, too. I was surprised to find it already installed on my system. :)