Many reasons 1.It's fun to collect all the beads. 2.They're pretty. 3.Every bead gives you a memory that you can wear everyday. 4.Everyone else has one. 5.They can have the style YOU want. 6.You can...
The clips keep the beads spaced evenly. This is functional - if all the beads end up in one place it puts strain on the bracelet and (worst case) it could snap due to badly distributed weight.