Crowley was a vindictive and cruel creature by nature, he hadn't been a human in centuries and his personal demons had personal demons of their own, he had sore spots, festering wounds, aching sores, had been stabbed in the back, betrayed, heartbroken and spat in the face by people he'd cared about more times than he could possibly count. It was a defense mechanism and by that a rule of thumb that he generally kept people at arm's length if he could help it, and he didn't make a habit of complimenting just about anyone because that wasn't his thing. Demons didn't compliment people, they didn't comfort people, they didn't pick people up when they were down and they didn't befriend and cheer them up.
The few times Crowley had done this were times he meant it. Dean Winchester was his best friend, someone he truly had fallen in love with, past tense of course-- he knew that ship had truly sailed and the more distance he put between himself and their ilk the sooner he would get over him for good. But Crowley's compliment to Michael was as genuine as they come, he really did mean what he said. He wasn't trying to knock Michael off his game and he certainly wasn't trying to kiss his ass or anything, he was truly trying to pay a compliment to someone who he was starting to respect.
It wasn't a smile, but Michael's lighter tone of voice was something that made Crowley feel better, it felt nice to know that he could cheer him up after delivering such soul crushing news. Hearing news like that made Crowley glad that he never had siblings of his own.
For a moment he looked a little hurt that Michael didn't appreciate his gesture but the expression was gone as soon as it had appeared.
"That's Officer Dick to them, though," Crowley quipped with a smirk, resting his arm on top of the bar as well with a gentle laugh. "But you're welcome. It wasn't very good news to be sharing, but knowledge is power, etcetera."
He shrugged a shoulder and heaved out a gentle sigh. He didn't want to make Michael uncomfortable with further talk, which left the conversation at an uncomfortable silence.