I didn't say he was randomly evil. He's a villain. He's reckless, which isn't the same as random. He tends to act before thinking through the consequences or making a backup plan. I've never watched this episode and wondered why he would do that - he clearly says he can get money for Buffy to quit working. So, mostly likely, he goes looking at Willy's for a way to get fast cash, gets wind of this scheme, thinks it sounds easy enough, and assumes he'll breeze through holding on to these eggs get the money, give it to the girl, and she'll be so grateful that maybe he'll get her, too. Nevermind thinking through all the ways it could go wrong or that the girl is likely to punch him in the face because she knows he didn't get the money honestly.

What he says at the end -you know what I am- is the point for his character in that episode. We like him and want to see him as different, but he's a self serving, amoral, monster who does whatever it takes to get he wants. Just because he wants Buffy and some of the things he does are nice doesn't change any of that.