Kia ora Koutou
Firstly you should practise all rescues in the conditions you wish to paddle in. Secondly a roll is my primary strategy of self rescue, yes it is as manoeuvre as mentioned above, it is a manoeuvre that allows the paddler to right his/her kayak after it has turn upside down, which is the primary purpose of self rescue. My secondary strategy is re-entry and roll and if this fails the paddle float re-entry.
Although I consider myself to have a bombproof roll on both sides I advocate for the carrying of a paddle float by paddlers of all skill levels. I have a close friend and fellow instructor who also has a very reliable roll. He took an unfortunate swim from his sea kayak in the surf after his deck was blown off my a breaking wave. He ended up spending tense half an hour attempting to re-enter his kayak in autumn conditions as night was falling, alone, several hundred meters off shore and with no hope of rescue. Had he carried a simple paddle float things may have been a lot easier. Fortunately he lived to tell the tail, but still continues to paddle solo.
Ka kite ano from Aotearoa NZ