Also you're missing out on opportunities that are outside of your field of expertise.

Just the other day I was watching Stanford's talk by David Friedberg about how he built the Climate Corporation which, in my words, provides bad weather insurance for businesses and farmers. The guy doesn't own a farm or a business that's impacted by weather, he's not a user of his own product, but he still went ahead and understood the intricacies of that industry and was highly successful.

Being your own product's user is fantastic, I think it really helps, however you'll be leaving out a lot of good ideas on the table.