Join Date: Oct 2008
Posts: 4,452
First, realise that due to the payout-structure, chips arent worth equally as much. Usually chips won are worth less, than chips lost. We got a formula, we call it ICM to calculate this. Sometimes some people call it "Bias against confrontation".
If you understand this concept, you might already be able to answer your questions yourself partly.
As this is one of the reasons for smaller bet/raise-sizes, your opponents need stronger hands to enter the pot to beginn with, hence you can lower the bet-size. Another one would be the usually smaller stacksizes, so even if you just minraise and get one caller, you can still be all-in with a bet/bet/bet line by river.
There are more factors, but in short it is a combination of maths indicating that its the proper play and player tendencies. For example in 9man-turbos it used to be standard for many regs to play less than 10% of their hands, making min-raises from mid-position onwards insta-profit moves (assuming you dont spew postflop).