Only with glass seed beads is it a question whether to use tigertail, or a nylon thread, because sometimes, with seed beads as the only beads on the string, the tigertail makes the finished piece a little too stiff. It is better than thread. The holes in beads are really jagged edges, like a broken bottle. They slowly saw through threads, when the piece is worn or moved. Tigertail is better than fishing line.
Fishing line dries out and cracks and breaks.
Tigertail comes in different thicknesses. It's not too thick so the piece lays right. It's not too thin, so the tigertail doesn't break.