The simple answer is yes; they’re definitely a worthwhile investment! Electric toothbrushes (especially the rechargeable ones rather than battery operated ones) have been shown to be more effective at removing plaque than manual toothbrushes.
The tooth bristles do all the movement for you so it’s also much less work and a simpler process all round. The timers on the electric toothbrushes are also helpful to ensure you’re brushing for long enough. For those who have a habit of brushing too aggressively, the brushes with pressure sensors may be useful.