When to make a small bet in two-player Haggis?

Question

In the game of Haggis, you can make a big bet (30 points) or a small bet (15 points).

I've always wondered what the use is of making a 15 point bet instead of 30. If you're pretty sure that you're going to win, why not make it 30? If in doubt, then don't bet at all.

The only situation that makes some sense to me is this:

Let's say you're winning (e.g. you already have 200 points in a 250 point short game), and your opponent is a bit behind you (e.g. he has 180 points). Your opponent doesn't bet. You've got yourself a pretty good hand, and usually you would bet big with those cards, but in this case, you can win the game just as well with a small bet. Also, in case something goes wrong, you are giving your opponent only 15 points. There is a chance that this won't be enough for him to win, so you will have the opportunity to respond in the next round. If you'd bet 30, it probably would be enough for him to finish and win the game.

Are there any other situations when making the small bet is a good choice?

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Edit: I should have pointed out that I'm asking this question about games of Haggis involving two players, but not three.

Answer 1

This question was discussed in this BGG thread.

The only answer I found at all convincing was: in a 3-player game, if your hand is marginal, the big bet may convince your opponents to put their own interests aside and work together to set you. If you make a small bet on a similar hand, your opponents might play less aggressively to defeat you--each trying to snag more point cards himself, say--leaving you with a slightly better chance of making the bet. Clearly, this does not apply to 2-player.

It was also pointed out that the 15-point bet allows a risk-averse novice to experiment with the bet mechanic without being buried for failure. This isn't strong general strategy but it's a reason you might see the small bet.