Catchy name.
I use a fusible thread for applique. Just not this one.
But I don't sew with it. I unroll a length of it & spiral it onto the base fabric under where I want my applique to live. (using it like I would a few dots of glue...just to hold the applique in place until I sew it down). I can stack (overlap) applique applique pieces and keep them in place until I get to the machine.
This works great for landscape or collage type quilts when I need to hold lots of pieces down before actually sewing them in place. I can decide how much or little thread to use for each piece, & a bit of thread fits easily under tiny pieces. It's just a bit less messy than glue.
But you do have to be careful not to get any on a hot iron.
It also works great in a pinch for things like hems. Or making ornaments where you might normally use hot glue.