Sure, no problem it's your site after all. I just posted that to give an idea how you
could do it, not how you
should.
It depends on how you use the portfolio site I guess. If your referring to it after someone saw one of the maps in action you may be right.
But I think that if a developer would scour (the many) portfolio's in search of a leveldesigner he'd like to have a handful of pictures that give an overview of your map instead of actually playing the thousands of maps you and many other mappers make. That's not a case of being lazy or not, it's a case of a crowded market and being busy. You're the one wanting to be a leveldesigner, and you're not alone in that. If you are mailing a developer with a link to your portfolio, you better give them something to see or your application will go to the bottom of the pile. And imho you should want to stand out of the crowd.
Note: I'm no leveldesigner or have the wish to be, and have no real knowledge of how you get hired in the gaming industry. But I think that it'll work the same in every field.
I was contacted by a developer once though, and that was because I made a mockup of a new and improved GUI of their game which got a lot of attention from the other betatesters. They could see directly what I could do for their game. Sadly they were they 'shoot and forget' type that said "We want to collaborate" only to be never heard of again. That developer has that name in the community and the game itself isn't that great imo so I dont know if I should be sad it didn't work out or be happy my name isn't attached to the game/developer. The experience itself would've been cool though.