Every time you use a private key to authorize on the service / DEX-uncomfortable, because of this preference is given to “hot " services
Using Get-sign, your DEX can become a “cold” service that will elevate your service in the eyes of the blockchain community.
Many people do not understand Metamask and analogues
Browser extensions are convenient but not good enough for mass use.
Browser extension or other strongly narrowthe circle of users for technical reasons
Extensions are not possible to use from mobile devices. Most of them are only suitable for a specific browser.
Using a private key is even less comfortable forthe user than Browser extensions
Cold storage of private keys is the safest but also uncomfortable way to use.