I found it most useful for expanding my horizons as to what is edible and/ or medicinal and/or attracts pollinators and/or accumulates minerals.
Having sampled some, I understand why most of the novelties I've tried are not on the grocer's shelves

And some the chickens eat long before I get there (e.g. primrose flowers). But there's a lot more perennial veg than I realized (the tradition of starting seeds at the beginning of the year and clearing beds at the end, in short, cultivating annuals, is really ingrained in our gardening culture I think), and I find it's a quick and easy reference work for the low down on anything I'm entertaining adding to the garden. Growing well here as perennials and you might entertain for your gaps are e.g. mallows (inc marsh) - and the chickens are very fond of their fruits btw -, angelica, perennial rocket, good king henry, sweet woodruff, ground ivy, lovage, sweet cicely, sorrels, plantains, solomon's seal (yet to try this; need to move fast if I'm not going to miss it, as the shoots have started breaking into flower), day lilies etc.