Handrails come in many design forms and from various materials, but whichever type you choose, they essentially serve the same purposes.
A handrail is a means of providing one or more of the following functions:

a. A handhold to offer support and assist in climbing or descending a stair of ramp.

b. Edge protection between differing ground levels to prevent falls from a raised level.

c. Delineation and separation between flows of foot traffic, generally if moving in opposite directions.

Whichever style of handrail that you choose, they will have been designed to satisfy these basic requirements. Also, if purchasing in the UK, they will be capable of meeting the requirements as set out in part K of the building regulations and BS6180 Barriers in and about buildings, if correctly installed.