Explain the purpose of the hydra's bud?

Hydra is a tiny animal from belonging to the phylum
Cnidaria and the class Hydrozoa, that lives in ponds and lakes. Animals like jellyfish,
sea anemones, and corals also belong to the same class of
animals.

The hydra, which has one of the simplest
structures among all the many-celled animals, is shaped like a thin cylinder about as
thick as heavy thread and is 6 to 13 millimetres long. One end of its body attaches to
sticks, stones, and water plants.  The other end contains the mouth, which is surrounded
by five to seven tentacles that act like tiny arms. The hydra usually stays attached in
one place for some time.  But it can move about by slowly along the bottom of the pond
or lake, or by drifting beneath the water's surface
film.

Buds in hydras are small, knob like growths that
appear on their body and enable hydras to reproduce. These buds develop from time to
time, and as they develop grow tentacles.  When the buds are fully developed, they break
off and live as independent hydras.