I'd like to point out that whips in 5e are not "as effective" as daggers. One has the reach property while the other has the thrown property; Daggers, as a result, actually have wider range, making them more generally useful. Whips have a wider reach for purposes of attacking from outside of Opportunity Attack range while widening your own range, but there's only so much you're going to be doing with a 1d4 opportunity attack either way.
That "reach" attribute does, however, give the weapon some tactical flexibility. In a pen and paper setting, in particular. It's a much better weapon when you can look at your dungeon master and describe precisely what you intend to do with it than it is when you're just looking at it as another 1d4 damage weapon. If Larian were to include it, they could bring this trait out by giving it some unique short-rest weapon skills.
I think all of this weapon-advantage-and-disadvantage-in-the-real-world talk, though, as fascinating as it is, kind of misses the point. In Dungeons & Dragons, you might be stuck with mundane weapons in the early levels, but as soon as you hit the +1 enchanted weapons on up, conventional martial-weapons historical accuracy takes a back seat. A whip that is enchanted to hit harder and injure more effectively is a whip that is no longer bound by the "it's a tool, not a weapon!" logic that has been brought up here. A whip that is enchanted to cause bursts of fire or lightning on impact is going to be intensely more lethal than the "tool" it was based on. A whip enchanted by some long-dead slave-driving mage to instill magical fear in creatures it impacts does not benefit from "but whips are terrible weapons IRL" talk.
And guess what kind of weapons you'll be using for ninety percent of any given Baldur's Gate game.
That's right! Longsword +1. Shortsword +2. Longbow of Silence +4. Et cetera, et cetera, and so forth.
You're using the weapons that don't exist in the real world, in other words.
