Agree with other posters - it's either high cost, or flaky, or both. Even the expensive ones require replacements a bit too often, and you'd have to be worried about some false measurements firing off excessive over-watering.
The 'water well' pots may be a simpler, cheaper, reliable option -- if you can hook up multiple inverted water bottles, or some ballcock arrangement into a cistern and share out from there with 13mm pipe -- if the bottoms of all your pots are the same elevation.
There's a small period of time while the roots head down to find water, that you need to top-water, but, again, convenience .vs. cost .vs. resilience tradeoff.
The 'water well' pots may be a simpler, cheaper, reliable option -- if you can hook up multiple inverted water bottles, or some ballcock arrangement into a cistern and share out from there with 13mm pipe -- if the bottoms of all your pots are the same elevation.
There's a small period of time while the roots head down to find water, that you need to top-water, but, again, convenience .vs. cost .vs. resilience tradeoff.