Pro: It's faster and quieter than a hard drive, possibly increases battery life, more reliable since no moving parts, but they do have a finite read/write life so it doesn't mean you don't have to back up data.
Con: They are wildly expensive on a per/ GB basis, and relatively small capacity vis a vis hard drives.
In the end their practicality depends on how deep your wallet is and how many apps and files you need to store on your machine.