I don't think it matters that much whether it's a Keurig or any other coffee maker on the countertop. My guess is a soda machine will probably be used with less frequency and may be kept in a cupboard (that's actually where I keep my coffee percolator) and pulled out for usage when needed. The new water dispensers will accommodate a "plug and play" Omnifrio machine OR a coffee maker so early adopters may just go that route.
It's just gravy anyway - the mainstream water business should thrive regardless - the Omnifrio is another one of the "razors" designed as much to sell more water "razor blades" at a higher margin. If it really takes off so much the better - it will add "S" cup sales and CO2 cartridges into the mix as additional "razor blades" recurring sales.
Billy Prim is 100% entrepreneur and always looking for new avenues - like "Primo Pure Ice" - that itself could turn into a big product. They came up with a lot of new products and concepts with the Blue Rhino business and will doubtlessly continue innovations with Primo. I'm pretty impressed with what they have already done - especially once I see the numbers laid out like the dude in the SA article did.
I agree with most of your post, and I also like that Ominfrio was an acquisition. It helps me rest assured they are healthy and moving in the right direction. I think the frequency of use depends solely on the individuals and also how good they make it. I think about the frequency a family of 4 drinks a coke. Lunch and dinner on weekends, dinner during the week. Maybe 2 cokes per day being safe? I can't see it getting pushed aside unless it becomes overly expensive as a substitute for cans, or is too time consuming/hassle to use. Either way it will get purchased, especially given the launch timing. The bottom line, as you touched on, is that the company is growing and expanding consistently. I am really happy with the stock and look forward to seeing what happens over the years.