The basting stitches are put in with a special soft,weak cotton thread which comes in a variety of thicknesses and weights. It is made slightly hairy so that it grips the fabric. It can leave an impression, so the correct thickness must be used for any given task. Silk facings on a dinner coat for instance must be basted on with very light thread and then removed before it is pressed. Also, removing them is tricky and they should be cut every couple of inches so that there isn’t too much tension in them as they are pulled out, as this can lead to them cutting the fibres in the fabric and making a hole. A mistake you only make once!
The bastings in the pic will come out and leave a little impression but when the garment is finally pressed (as long as it is done properly with just the right amout of heat, weight and moisture) it will disappear.
Not sure what it looks like to anyone else because I am in the trade but don’t think that hours and hours are spent putting a pair of facings on. Gino only touches anything once and does this at such a pace that it is easy to miss what he is doing. He makes it look very easy. There is a huge amount of work in a morning coat but if I needed it in a day, I expect he could turn it around in twelve hours at a push and with no compromise at all in the quality. He would probably be shot for the rest of the week though!