The two most significant advantages in the form factor of M.2 SSD are size and capacity. For example, it uses very little space inside an ordinary laptop, making the laptop very compact and easy to carry. M.2 SSD uses a lot more power than a simple SATA or SAS interface because it has no moving parts. They also use their chips in phones, which have the capacity to store a lot of data.
The M.2 interface is a multi-function platform that configures PCIe, SATA, USB 3.0, Bluetooth, and Wi-Fi. If you have a laptop that consists of an M.2 interface, then it will be available with lots of input/output devices configuration options.
M.2 SSD capacity key disadvantages are prices and lack of not being so common. Prices of 2,5-inch SATA SSDs have also decreased exponentially, as they were manufactured in greater numbers.
A 1 TB SATA SSD has been around $99 or less in recent years; relative to the price of the SATA drive, an equivalent size M.2 SSD is around two and a half times higher. Restricted storage is another disadvantage of the M.2 SSDs. Although 1 to 2 TB is likely appropriate for most mobile applications, M.2 would need higher capacities to find its way into more corporate storage systems.