It depends on what you mean by hard use. If you mean abuse, then it's not as tough as some other folders. If you mean lots of use, yes, it will serve you well for years and years.
The blade is a very resilient steel and it will bend rather than break. I've seen H-1 blades bent 90 degrees in a vise. The nature of Salt folder means it lacks steel liners like other FRN Spydies so it will twist and bend more, but that also means it will absorb impacts vs breaking. If it's constructed with pins (earlier version), you won't be able to tighten it back up as easily as newer versions with screws. That means a lot of twisting can loosen the pivot over time.
It will stand up to a lot of uses, but no, I wouldn't try and chop down a tree with it.

Corrosion-resistance wise, it's probably as "hard" as you can get.
H-1 will get stupid sharp but that mostly depends on the person sharpening. The steel is work hardened so edge holding will get better the more you use and resharpen. Initially, I wasn't impressed but after a few months of use and several sharpening sessions, my PE Salts seem comparable to VG-10 or better. Compared to some other "super steels" it's fairly easy to sharpen.
For me, "hard use" is really "hardly used" for most of my folders.

Too many knives, too few uses.