Most "authorities" would say, we play short so that we can "get full value" from the weaker players at the tables. Maybe this was true back in 2006, when bad players would stack off with top pair no kicker for 150 big blinds like it was going out of style. But today, even the so-called "fish" are a little more discriminating. Many might even hesitate to call more than 1 or 2 streets with a weak top or 2nd pair, since there is the ever-present leverage of the money left behind for future bets (although they might call 30-40 big blinds against a short stack with these hands).
But beyond specific tactical situations such as the one above, playing a small stack has numerous passive benefits. In fact, just buying in short removes many potential leaks from our game. Furthermore, just sitting down at the table with less than a "full" buy-in, tends to drastically alter the table dynamic. If other players don't notice and adjust, we profit.
I covered this in my first book, Automatic Poker, so I will but briefly enumerate the inherent advantages of playing a short stack.
Reason #1: Not Many People Understand Short Stacking
This is one of the positive consequences of the general poker population being so anti-short stack. Rather than accepting buying in short as a viable way of playing, most seem to completely shut themselves off to the idea. Instead, they focus on full stacked strategies and largely ignore what they refer to as "parasites" are doing. This allows us to fly under the radar, somewhat, and make additional profit from their collective mistakes against us.
Reason #2: If We Screw Up, It's For The Minimum
If uncertain about a play, it's impossible to lose more than 30-50 big blinds at a time. This fact also makes for an easier learning environment. Losing a bunch of buy-ins in a session hurts a ton less as a short stack!
Reason #3: Less Brain-Racking Decisions
When playing a 100 big blind or bigger stack, most of the tough spots come on the turn in 3-bet pots or the river in single-raised pots. But a short stack almost never has to face these difficult decisions. We were already all-in before it came to this!
Reason #4: We can WTF Shove All-In At Any Time
It's almost never a giant over bet when you start with 20-40 big blinds. Sometimes there are simply no good turn or river cards, so we can just stick it in now, and it's out of our hands. This ties in to #3, and being short gives us yet another tool to avoid tough spots.
Reason #5: We Look Like A Fish
One of the most common reads that full stackers have is that when a player buys in for less than the maximum, he is likely a fish. So, when we sit down for the minimum, we are instantly treated like a n00b for at least a couple of revolutions. The benefits of this type of image are numerous.
Reason #6: "You Talkin' To Me?, You Tryin' To Bluff Me?"
Against players who like to bluff often, our stack size dulls the edge of their sword a bit. Many will just play more straightforward against shorties and, instead, try to trap them.
Reason #7: Set Mining Against Us= -EV
Due to a lack of sufficient implied odds, it's almost never correct to set mine vs. a short stack. So, if you get it in on the flop against a set, just remember that most of the time, your opponent made a grave error.
Reason #8: Less Money At Risk In The Bankroll
Sure, short stacks can play higher stakes with less bankroll, but they also risk losing less money if a poker site, God forbid, goes belly up.
Reason #9: Bad Days Aren't As Bad
I am talking about playing in a less than optimal state of mind. Since short stacking is a lot more straightforward and automatic (yeah, I said it), it's hard to play terribly bad or lose a ton of buy-ins, even when tilty.
Reason #10: Less Study Of Opponents Necessary
You still have to exploit opponent tendencies; however, most of the time you will not get into long-term leveling wars with other regs. The only time this has ever happened to me is against super aggro 3-bettors, and that's nothing complicated enough to write home about.
In summary, there are numerous facets of short stacking that more than offset the value we lose against full stacked fish. The awesome thing is, we don't have to think about it. We just have to buy in for the minimum, and profit.
I hope you've enjoyed reading this as much as I enjoyed writing it. Additional details about this topic and more can be found in my book, Automatic Poker.