It's not a particularly good deal for the ACC but its an improvement over what they had. These specific packaged games were previously on RSNs (regional sports networks) carried on cable. That could be anything and vary from market to market. One place could be a Bally Sports channel. Others it could be MASN or NBC Sports (insert local channel). And not every cable package had them. So fans didn't know where to look or if they even had the games. The CW is OTA just about everywhere. More people will be able to see the games now.
With The CW recently being purchased, they're making more of an investment in live sports*. They don't have the money of NBC, FOX, or CBS, but it could grow in the coming years. Financially, this doesn't do much for the ACC but it is an improvement over what they had.
*One of the reasons they're doing this is because of the fun fact I pointed out earlier, the CW's audience is actually older than one would think. Older populations watch live sports in larger numbers than the younger crowds. Another fun fact; sports viewership for 25 and under is drastically lower than previous generations across all sports. Will they grow into it? Maybe. But so far it appears that some just aren't into sports and two, most of them consume them in different ways (via social media and such instead of just watching live games)