I used a combination of Plant and Shrimp in my first fully planted tank, it worked very successfully. However I found it to be a nightmare to plant shallow in it as it is a very light medium and high tank flow or fish would easily uproot plants, planting deeper improved the situation. It's a brittle substrate and If it dries out it is extremely friable (think rice crispies) and goes to dust. Even when wet the mechanics of deep planting can easily crush it so you have to be gentle with it.
As for it containing nutrients I can't really say as I was dosing full EI. The water it received was remineralised RO/DI with Bee Shrimp Mineral GH+ to GH6, if any KH went into this tank the substrate scavenged it all so the water always read 0KH on measurement.
I had a lovely S.Repens Carpet in this tank until it experienced Plantmageddon. I made an autodosing mistake in this tank and a month or so of Micro (EDTA chelated trace) ended up in it, I rectified that mistake quickly and performed a large 75%ish water change (it already had a 50% change earlier as the accident happened when I was reintroducing the micro manually and forgot to turn the timer off), I then dismissed this would give me problems as Ian_m always likes to repost his Macro dosing accident anecdote and its ineffect on his tank, it's a good anecdote so no problems right?
Over the course of a few days the tank went to sh*t literally, complete meltdown, I couldn't work out what was wrong. Now I have to say here I use a CO₂ controller, it was working in 0dKH water (200TDS) and I was beginning to think something was going haywire, no change in read pH but the dropchecker was progressively yellowing and fish were starting to gasp at the surface, the plants didn't look happy, something really bad was going on. The controller behaviour was telling me the KH was rising when none was being added (this prompted a bout of unsaid severe paranoia suspecting sodium bicarbonate sabotage, salted tank), I tested the water and the GH was about 14 and the KH about 12, like wtf! It took me a while to work out what had really happened and my conclusion was this, the Micro dosing accident caused the Stratum to disgorge any GH and KH it had stored over time through Cation Exchange and replaced it with the overdosed Micro.
I won't use it again (using JBL shrimp soil and it is a heavier and denser material making it easier to plant in) but that's not saying it's bad, it's got a high CEC so it is a good substrate to use even when dosing EI, just don't make any overdosing mistakes with it especially with Traces.