Sure. All of these things are valid things to do, and they all are in support of the same goal-- making the game as fun for the players as possible.
If a bad guy receives a critical hit for like 52 damage and drops down to 2 remaining HP... cutting that long fight short by having having him throw his hands up in surrender versus just having him fall over dead/unconscious from that critical hit both accomplish the same thing. And which way you do it all depends on your particular style. But one is not defacto "better" than another because no one is judging how you DM and scoring you points. No one else cares how you do it.
Unless of course you genuinely believe your own style of play is the "right" one and everyone else is playing wrong and you think you're going to get a trophy at the end of the year for playing the "right way". In which case, best of luck to you!