I thought about that but decided it was not actually a plus for the 8 point over the 7 point. Once the checkers are home it is weaker. Then the 6's you are worried about is not a plus for the 8 point. With the 7 point 61, 62, 63, 64, 66 clear the point. 65 could give a double shot. With the 8 point 65 is probably a single shot but the cleanup is harder. Also the other 6's do not actually clear the point.
Compare the following where the 8 point is .05 weaker.

              
 
              
 | | White is Player 1
score: 0 pip: 62 | | 9 point match | pip: 115 score: 1
Blue is Player 2 | |
| XGID=-BbDCBBB-------a-a-cccb---:1:-1:-1:21:0:1:0:9:10 |
| Blue to play 21 |
| 1. | XG Roller++ | 10/9 4/2 | eq: -0.705 |
| Player: Opponent: | 16.58% (G:1.47% B:0.04%) 83.42% (G:8.78% B:0.12%) | |
|
eXtreme Gammon Version: 2.10, MET: Kazaross XG2

              
 
              
 | | White is Player 1
score: 0 pip: 64 | | 9 point match | pip: 115 score: 1
Blue is Player 2 | |
| XGID=-BbDCBB-B------a-a-cccb---:1:-1:-1:21:0:1:0:9:10 |
| Blue to play 21 |
| 1. | XG Roller++ | 10/8 4/3 | eq: -0.654 |
| Player: Opponent: | 18.27% (G:0.78% B:0.02%) 81.73% (G:8.15% B:0.12%) | |
|
eXtreme Gammon Version: 2.10, MET: Kazaross XG2
Maybe though the 8 point is stronger when there are still checkers to bring around. If give us the 12 point to bring home it is extremely close with the 7 point still being better but by only .006.

              
 
              
 | | White is Player 1
score: 0 pip: 79 | | 9 point match | pip: 121 score: 1
Blue is Player 2 | |
| XGID=-BbCBBBB----Bb-----cccb---:1:-1:-1:21:0:1:0:9:10 |
| Blue to play 21 |
| 1. | XG Roller++ | 12/11 4/2 | eq: -0.668 |
| Player: Opponent: | 17.76% (G:0.99% B:0.03%) 82.24% (G:7.77% B:0.21%) | |
|
eXtreme Gammon Version: 2.10, MET: Kazaross XG2

              
 
              
 | | White is Player 1
score: 0 pip: 81 | | 9 point match | pip: 121 score: 1
Blue is Player 2 | |
| XGID=-BbCBBB-B---Bb-----cccb---:1:-1:-1:21:0:1:0:9:10 |
| Blue to play 21 |
| 1. | XG Roller++ | 12/11 4/2 | eq: -0.662 |
| Player: Opponent: | 17.73% (G:0.96% B:0.03%) 82.27% (G:7.42% B:0.21%) | |
|
eXtreme Gammon Version: 2.10, MET: Kazaross XG2