As someone that has to answer to an editor about perfect sharpness ALL the time, I can speak to how overated sharpness is in the grand scheme. However, I also understand the value of it as a way on creating an image.
A compromise must be made, IMO. And although it's not really the lack of sharpness that bothers me in a holga, i find the fact that each roll to be unpredictable to be unsuited for my sort of work.
I like to pull a roll out of my developing tank and have my heart racing to see if i got a beautiful moment, or a composition that was spot on. And the moment I see "that shot" (those who've pulled wet film out of dev tank know what I mean) I'm in heaven. With a holga, a camera that i must have put over a dozen rolls through, i found myself mostly excited because I was anticipating to find at least a decent exposure. Composing is difficult, even very approximate exposure is difficult, focusing is a joke. Is it simple? Yes, very, at the cost of all the other things that matter to me, i think so.
As a photographer for a newspaper, and as a street photographer, i work on both extremes: very sterile and technically good images, and personal images that require very little technical perfection. I work, or have worked with Nikon D200, D300, D700, Canon 5D, 1D MkII, Nikon film SLR, Leica M, Hasselblad 500, TLR, Holga, Point and Shoot digital, APS cameras...
Many of these were cameras that i borrowed from someone for a week, or a short fling that past, however, many of these did something that another camera did not as well. Shooting a hassleblad felt like perfection, no compromise on build quality, image quality, user experience... Using a Canon 5D was an epiphany as to what digital could really do. My Leica M6 is pure joy every time i use it, desperately simple (my meter died and I haven't bothered to change the batteries). I found a holga to be bothersome and to interfere with the photographs i wanted to take as opposed to allow me to see things differently. I found myself saying: " can't take this shots, it's too dark in here, can't take this shot, it's too bright out here, can't take this shot, it's too close, can't take this, i can't see what I'm looking at through the viewfinder...
And when i did get an image i liked, it never felt like an image that i wouldn't have been able to get with another camera. All in all, i found a holga to be a fun toy but a crappy tool. Give me a model that has a couple real shutter speeds and a halfway decent viewfinder and i'll try it again.
Their is a difference between simple and lack of control and predictability, the holga crossed that line (for me), but hey, some photogs, like the one mentioned at the top of this thread seems to use one quite well. I don't think however, looking at the images, that any of them benefit from being shot with a holga as opposed to say a mamiya 6 or 7.
Sorry for the rant 🙂