My point is that very few people are blindly just taking numbers because they know they are profitable alone. They are looking at many more variables. For example, four games this week were +14 and +9.5 (two each) and looked like they had a chance to close at those numbers. Assuming they did and you blindly played them every single time they were available, you should do well in the long run. But if you had +14.5 and +10 you will have an overwhelmingly better ROI. It is even cheaper to buy the 1/2 point off these numbers because they are not as key as 3 and 7 are. For sure a smaller sample size but +14 covers at 53.2% and +14.5 at 75%. But the noticeable thing is +14 the MOV is -14.95 but the MOV for +14.5 is -5.69. +9.5 covers right around 50% and the MOV is -12.33, but +10 covers 58.3% and the MOV is -8.76. There is player psychology and motivation to consider when a large key number is put up also.
The other issue is the playoff considerations. There was a nice long article on this online explaining how this is largely baked into the line but folks still insist there is wriggle room. Maybe, maybe not. For example, the main game that they say might matter a lot to the line is if the Ravens win/lose — what do the Chargers do?
My long-winded rattle here is to say a couple of things. People know about key numbers but they are not blindly betting them. They are using other factors as well. This is where their mistakes may come into play, or if they are good at it, their advantage. Just because a line is set at +3 it does not make it the same quality as another game that has a line set at +3. Just because 15% of games land on 3, it does not mean that +2.5 will land on 3 at 15% of the time. The data shows it to be closer to 10%.
Absolutely, if you know you are going to play a +2.5 and you know you can get +3 later for the same price you should wait. But how often does a line move from +2.5 -110 to +3 -110. Is it enough to keep on waiting and if it does not move, do you take the +2.5 at the very end — what if it moved to +2. If you see value at +2.5 -110, is it just the same or worse than +3 -120.
There are a lot of assumptions in here that I do not see the math holding up. Yes, if you add in some other human factors and handicapping factors, okay.