All of this is true, and you can't "work" a headworn mic like a handheld, but you do have a degree of control by adjusting the distance to your lips. The freedom of movement and eye contact has to be factored in.
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pa4X 76 ,SX900, Audya 76,Yamaha S970 , vArranger, Hammond SK1, Ketron SD40, Centerpoint Space Station, Bose compact