Aside from that they could at least provide a bulk download, which is another dick move by these walled gardens.
But Twitch says it won't be offering a bulk download tool for that purpose, sticking [users] with the daunting task of downloading and/or reuploading their clips one by one (or using dodgy third-party bulk download tools to do so).
Granted, a programmer or advanced user should have no problem with it but the potential for security incidents is huge for normal users trying to save their favorite clips.