What does the expression 方便倒是方便 mean?
方便倒是方便 roughly means though it's convenient. Usually it goes like 方便倒是方便, 可是 ... ... It implies there could be some other negative factors or concerns (though it's convenient). 

E.g. (quote from online): 


  方便火锅方便倒是方便, 其安全性又是另外一回事。