Depends on the era in which you're talking.

THF has good eva, which obv helps solo certain things.

75 bloody bolts were a large help, the ability to sleep bolt and TA NPC was also lovely.

Abyssea, kinda goes without saying.

Currently, glasscannon THF excels at killing the enemy before it kills you.

I would say something to the lines of: "The players who use THF are of a higher caliber than your standard issue player." But there are Thieves among us that make us cry, so.