specialty rulers are always kind of...*do I really need that?*, is it worth it?, should I buy it?* and really.... it's a personal thing. yes, you can (often) accomplish the same thing with out it~ yes, you can live without it~ yes, it is kind of expensive~
so, you go along for a quilt or more without it- making do with what you have.
then one day someone buys you that special ruler as a gift- knowing you make *those kind of quilts*, you use it---and wonder....*Why in the world did I not get this ruler ages ago....this is wonderful!; or, you try it once- decide....I hate using this - and never use it again...it's really hard for one person to tell another one that you "Need" this ruler---but you might.
I was that way with my 'add a quarter & add an 1/8' rulers. I did paper piecing for years- successfully- using my usual rulers. then someone put an add a quarter ruler in my Christmas package...oh my goodness- I love it! I wonder why I didn't pick one up years ago- now I always use it- and bought the smaller one for those tiny paper pieced blocks- sure I can paper piece without them- buy why would I? they have simplified and taken my paper piecing to a new level I love!
I know people who have bought the log cabin book, with ruler- and love it- use it all the time- me, I still make my log cabin blocks without it, but I do wonder- if I tried it out- would I love it? maybe...will I try it? probably not, because I don't tend to make a lot of log cabin quilts- if they were my 'go to' pattern I would probably take the leap.