To clarify further, there are two different kinds of “low” poker games. One is the one in which you’re trying to make the absolutely worst POKER hand. In that game, the winningest possible hand is 23457 not all of the same suit. This type of game is sometimes referred to as “deuce to seven”, in recognition of that hand. A game typically played with those rules is “triple-draw-low”, which is 5 card draw with three rounds of drawing and betting.
The other kind of low game, which is as far as I know exclusively played as the low half of high-low split, is totally unrelated to poker hand rankings, and simply involves the 5 lowest distinct cards, with ace being low. In games of this sort, suits are irrelevant, and A2345 is the nuts.
Two further things complicate this:
(1) Some hi/low games are “declare”, and some are “cards speak”. In “declare”, a person announces (usually via simultaneous reveal of 0, 1 or 2 chips) that they wish to win the high hand, or the low hand, or both. In “cards speak”, everyone just shows their cards, whoever has the best high hand wins high, whoever has the best low hand wins low. This is a crucial distinction. Suppose you have a hand with A2347 all the same suit. You have a very good high hand (ace high flush). You also have a very good low hand (A2347). But both of your hands might be beaten. If two other plays are both in the pot and betting like crazy, you might figure that you’re beat. But is your high beat? Or your low beat? Or both? In a declare game, you have to figure it out and guess right. In cards speak, you just have to hope that you aren’t facing both a full house and A3456.
(2) Some low games have a “qualify”, meaning that a hand has to be sufficiently good to even be allowed to be counted as a low. Generally, the qualify is 8-or-better. Thus, 45678 is a legal low hand, but A2349 is not. Omaha hi/lo is basically always played with the qualify, meaning that many times, no one has a low hand at all. Generally, cards speak games have qualify, declare games don’t. In a declare game, if you declare low and no one else does, you generally win half the pot, regardless of your cards.