Canna Coco's recommendations are based on using pure coco without perlite, so there is a difference there. Sure you can do it without multiple daily feedings and no runoff, if you are using large containers full of straight coco and relatively low EC. There are some drawbacks to that however, similar to the same drawbacks you get in recirculating type systems, in that the plants will pull the nutes they need most, and leave the others behind, thereby resulting in fert imbalances. The beauty of a drain to waste system with multiple feedings, is that you ensure proper nutrition rations are always available to the plant, and you can also get away with much smaller container sizes and less media. I'm guessing that canna coco doesn't want you buying less media, because that results in less sales for them. Same with perlite; if you fill your pot up with 30% perlite, that's 30% less sales for them. I've cannabis in coco for over a decade in all kinds of pots (big, small, wide, narrow, etc), and in varieties of media mixtures (straight coco, coco/perlite, coco/ricehulls, etc). In my experience the plants in large pots of straight coco which are only watered occasionally always did worse. The plants with smaller pots in coco/perlite fed 4x per day have done much better.