Plasma enables Ethereum to perform up to 2,000 transactions per second instead of its actual capacity of 15 transactions per second. However transactions happen off-chain but sufficiently guarantee about security. Plasma can be thought as side branches to the main Blockchain tree carrying out operations inside them and then transforming them back to the main chain. As a lot of tasks will happen out of main-chain, the process will be fast. Therefore, it is necessary to give Ethereum users a new level of user experience.
Natalia.McGregor Answered question