For someone learning music, nothing is harder than keeping up with the right tempo. A Piano accompanist would help with this by adapting to you but also pushing you towards your target tempo at the same time. The tempo regulator follows the same logic by drawing you note after note towards the tempo you had initially set, while adapting to you.
To activate the tempo regulator, setup your desired tempo on the score, activate magic mode then drag the score settings up, go to the Performance tab and switch the Tempo regulator on.
The tempo regulator can provide a smoother tempo experience than magic mode alone, as it allows less speed deviations.