one reason parties use the media - that it reaches younger audience
One reason is because it reaches younger voters.
Facebook, Instagram, "X".
Snapchat are widely used by young people sousing these apps will allow political parties to reach out to the younger voters who traditionally don't vote. It is also very cheap and sometimes free to use, which saves parties money and allows for instant communication and updates so they can spread their messages quickly.
For example, the SNP has over 335,000 "X" followers, showing their popularity on the platform.