There isn't any news yet on whether or not there will be another season for the show.
As to why new episodes are all released at once, it's because of the binge-watching culture that's replaced the "weekly buzz" culture that traditional television brought and sustained for decades. Viewer habits have changed a lot since then. Everyone has DVRs now, which means everyone just records what they want to watch. And when they decide to watch their recordings, they'll typically want to watch it all at once, which happens because of other reasons depending on the person - busy life schedules, interest changes, lots of other shows to watch, etc.
Streaming services like Amazon Prime and Netflix know about this cultural shift, so they release their stuff all at once.