Bad? No.
The best option? No.
Adding any solid chemicals to the skimmer could clog your intake pipe (very rare but it has happened here). Also how do you know when it is all dissolved? If you add it, retest a few days later and get a number lower than you expected then we will just assume there is some undissolved in your filter. Without being able to visually confirm the CYA has been dissolved in to the water we will have nothing to go by. Putting it in a sock allows you to know when the CYA is fully dissolved while also preventing possible line clogging and keeping your filter free for cleaning at any time. That is why it is the option we prefer.