A strike throw appears to be a throw (in that there is no normal pushback), but is given the strike hitbox treatment.
In rare instances, there is a bizarre “strike throw hitbox” that does not conform strictly to the rules of the throw hitbox, nor to those of the strike hitbox (obviously, the details differ depending on where it is found).
When a strike throw hits, it locks and throws. Basically, if it doesn’t switch over to throwing, it won’t do damage, so if hits trade, it loses in the damage department.
In 3D fighting games, even when blocked, these may switch over to the throw anyway.
The King of Fighters series has its own idiosyncrasies where a strike throw does not always strictly fit the above definition; these are pretty endemic to the KOF series (starting in KOF ’96), but do merit closer examination, as they appear in SNK-type games pretty often, even recently.
This type of strike throw, like many particular command throws (sometimes known as “proximity unblockables”) in KOF, only begins startup when sufficiently close to the opponent, and yet it appears to be a strike.
The first step is unblockable, or guarantees something like a guard crush, but in the former case, it is defenseless against autoblocks in the same way as other unblockable moves.
It doesn’t lock the opponent, so if they manage to jump (etc.) before the move can hit, it will often glance off.
Because the move is a strike, it won’t touch an opponent during their emergency evasion, though it must be said that emergency evasions are designed not to go behind an opponent in the middle of their strike throw, and most strike throws do multiple hits, so in most cases, they will still hit the evader when they are open at the end.
However, moves for which the interval of the startup of the attack hitbox is long may not hit that opening so easily, and there is a possibility that they may be stuffed, or (at least in cases where not all hits are unblockable) blocked.
The strike throw system was greatly modified in KOF XI, so that the first step would not have a normal strike hitbox. Thus, it will not touch an opponent in midair.
The only difference with throws, then, is that of the locking; depending on the range, there are cases where strike throws will not do the full number of hits.
Also, in XI, there is only one move that fits this description: Shingo’s Shingo Kinsei – Ore Shiki: Nie Togi.
Because nearly all of the strike throws in KOF are not 1-frame throws, the startup is slow. For that reason, super special moves that are strike throws are a dead giveaway due to the super flash, making them hard to use.
In KOF ’98 on and afterwards, where there is an animation for command throw misses, where strike throws can just barely be evaded, the move may just misfire as a normal move, so depending on the character in question, the risk may actually be quite low.