Hey Stone/Bode, those are some pretty good reasons, though, no?
I'll give Bode my standard invitation to come check out
#SIP Club if he has any interest in a deeper dive, but I think you hit some of the biggest advantages. Plants grow bigger with less effort simply because of the way the pots are constructed. There is a built in air gap between the water reservoir and the soil which provides a constant air source to the the bottom inner roots. And, because of the reservoir, the plant has constant access to water and nutrients so there is no pause in growth like you'd get from the wet/dry cycle.
The roots are essentially entirely the very fine feeder roots since the plant doesn't have to go searching for water. And, as Stone said, watering times are essentially non-existant. The total time you'll spend watering is however long it takes you to pour a gallon or so of water down a 1" tube.
Growing with them has some quirks, like I find it generally takes 2-3 weeks for the plant to convert its roots over to the roots it will use from the water seeking ones most of us start with, and if not done well can lead to droopy plants for a bit, but really no harm done.
I think I've also seen a dramatic reduction in the time for the flip to flower but I need more reps to be sure. I'm growing a new to me CBG strain that showed pistils on day 3 after flip when normally it takes me more like 7-10 days. Could totally have been the strain though. Emilya mentioned she thought she noticed some speed up in the plants she grows in SIPs as well. That is something we'll all have to pay closer attention to on subsequent rounds.
So, basically coco or hydro type results, but done in soil, and works with all kinds of media and nutrients. Like Stone, I grow using organic methods, but plenty of growers use bottled nutes, so it's a very flexible platform. And I think it is the ideal platform to use for growing auto's for most growers as improper watering is the most common cause of stunting those types of plants.
They are great for new growers because they take the learning curve away for proper watering, but benefit experienced growers as well. They're not for everyone I suppose, but I have yet to hear of anyone who's tried them that regretted the decision. I'll likely never not grow in them again and am converting most of my houseplants over to them as well.