I don't like the look of butt joints, so I will continue making them with my "scarf". Actually you spend very little time building the boat compared to its life, so the time I spend making joints on my strips is well worth it.Use butt joints and save yourself the extra work.
Another joint question for the experts
If you scarf join the strips before installing them, it makes a fair curve easier, so is likely to be more important if the join appears in a sharply curved region. The 1:7 (or higher) scarf is usually specified for strength in joining gunwale stock. For strips, as far as strength is concerned, you can do whatever you like, since the major requirements for the strips are to define the curve and to hold the glass layers a set distance apart. If you glue the scarfs with epoxy, they don't show up as well.
Alan