I have never used a blind for hunting turkey and probably will not use one as long as I am able to ride a bike or walk to find a turkey wanting to play the game. Sitting and waiting for a bird who isn't gobbling isn't my type of hunting though I might one day be so old or immobile I have to hunt that way.
But, I have spent many, many hours sitting in a blind while trapping turkeys for research. Turkeys usually aren't even the slightest bit concerned about a blind being in their comfort zone. I have had whole flocks of over a hundred turkeys walking past the blind within just a few yards, on both sides, to get to the trap site. They are just as unconcerned with a vehicle being used as a blind. Talking in the blind doesn't even mean anything to them. In fact it is like the human voice either doesn't mean anything to them or they don't hear it. I have talked to many turkeys that just completely ignored it as if they didn't even hear it. It is one of those mysteries of nature I have never been able to figure out, as to why some turkeys, in fact it seems most turkeys, don't react to the human voice.