Yes and no 
As the alpha channel is not always perfect, it’s better to use a suitable colour (e.g in case of vegetation –> green) -> otherwise you will probably see a yellow frame around your material 
You can either just add one single colour or there are also tools/plugins that are filling the background with suitable colours -> so that you get the perfect results (e.g in photoshop I use the solidify modifier from the flaming pear plugin)