I'm not opposed to thanking them, @LauraE. I've done it, and I encourage others to as well. I just don't like the option to send a PM. I think thank yous are largely why they're an option, if not the only reason. I don't believe SH reads every message sent to CHs. I think they read randoms, kinda like auditing messages, for example. But I don't know foresure.
But I asked because I'm thinking there must be something I'm missing. I think to myself, why is it important for some to go that route? So I asked. You gave me something to think about with it seems impersonal, and thank you for giving me your perspective. That's all I was seeking when I asked that question.