Healthy compost like ewc usually contains a good amount of fungi but it never hurts to add granular. It’s not as critical to have added myco fungi in your soil as it is cooking as it is to have it in the root zone at transplant. I add granular mycorrhizae at each transplant but only then. Would not necessarily call it a waste to add myco to the soil before there are plants growing in it but it’s probably overkill.
I agree, definitely borderline waste, adding mycos to soil is purely gimmicky IMO. Unless the mycos is making direct contact with the roots then it will do nothing. The only exception to this would be if your soil has been alive and undisturbed for long enough for the mycorrhizae to have successfully colonized the soil with their own "web" so to speak. Eventually, you won't need mycos anymore, as you'll have loads of mycos webs in the soil.
Mycos in amendment mixes make a little more sense, as many of these bags recommend putting 1-2 tbsp of the mix into holes prior to transplanting. As a result, the mycos in these amendment mixes are actually viable, as the mycos in these blends come into direct contact with the roots.
Even so, the mycos in soil/blends won't be nearly as much as what you'd get from a dedicated bag of Mycorrhizae specifically. Unfortunately, adding mycos into these soils/mixes is purely a marketing scheme that prays on ignorance.
Mycos can be had for between $10-$20, and it lasts a long time. Having mycos is absolutely mandatory, especially if you're starting in a new soil that hasn't developed life yet.
Mycos acts like a bridge, or a mediator of sorts between the plant's roots and the various microbes in the soil. Without mycos, that "bridge" is missing, and it will take weeks, if not months, until this "bridge" develops naturally in the soil (depending on the quality and age of your soil).
Mycorrhizae, like most everything else in organics, becomes superfluous once the no-till soil web has lived long enough. Eventually, you won't need to use mycos on your roots because your soil web will already be filled with mycos ready and waiting to attach to the next set of roots.
Until our soil has been "alive" for 6+ months, we will certainly benefit from using mycos. In fact, until the soil has been alive for this long, using mycos on the roots is absolutely mandatory.
Roots don't just spread out in search of water, they also spread out in search of microbes to form a symbiotic relationship with. Depending on the soil quality, this could take days, weeks, or even months. Again, dependent on the soil quality and microbe population. By applying mycos directly to the roots, now the plant does not have to search for this symbiotic relationship, and can immediately focus its energy on more productive matters.
Much respect love and happy growing to all thank you all!!