Let's say your day job you work at needs a domain registrar and you own a domain registrar. It is morally correct for you to suggest your own product? Or should you suggest something else purely because it's a conflict of interest?
I'm not sure that I would really want to offer some services from side businesses. There is a possibility that the company might end up expecting a higher level of service than was standard, since they were employing you. That probable wouldn't cause problems since it is just a domain register and the company just needs a few domains. Also, a few people might question your judgement on your recommendation with the conflict of interest. I wouldn't really be worried losing the few dollars to competitors.