Thread Identification Help – Cones Sewing Machines Parts and Sales in Los Angeles

I recently purchased a bunch of notions second hand. Fast forward a bit and I was looking at coned threads (like this red one in the middle) for sale that left me a bit surprised as all of the coned threads were said to be interlock thread and not good for general sewing, only for interlocking edges. Now, is this correct and I should keep my large coned threads for just locking up my fabric edges? Or am I incorrect and it’s fine for use making strong stitches in my clothing seams?

Thanks!