Motor disabilities like amyotrophic lateral sclerosis (ALS), or high-level paraplegia severely affect patient's interaction with their environment and independence. Brain-computer interfaces (BCIs) are an essential technology linking neural activity to external devices to recover lost functions. Advances in signal acquisition and decoding algorithms have greatly enhanced the accuracy and stability of BCIs; however, there remains much room for improvement concerning long-term biocompatibility and seamless integration within everyday life. This review analyzes the present role of BCIs in functional recovery among patients suffering from severe motor impairments, summarizing recent results obtained using both invasive and non-invasive modalities about motor rehabilitation and communication restoration. This analysis shows that although BCIs provide significant benefits in regaining autonomy they face technical hurdles and lack standardization in evaluation metrics. This paper provides here a comprehensive reference towards further BCI developments and highlight open issues related to system robustness and user adaptability. Further efforts should be directed toward optimization of closed-loop neuromodulation strategies and large-scale longitudinal clinical trials to enable wide practical use.