I definitely think it's a better option than grinding everything down. However, regarding the soil, it is always a combination of factors, so I would not forego the machine entirely.
Take the Hügel I helped build in Canada (there is a pic in one of these comment replies). We used pretty big logs, but that was not all. Since we had a chipper at hand, we also added a layer of wood chips, along with leaves, straw, manure, and actual soil. Sure in comparison the soil and the manure were of modest quantities, but they are important to help to get the decomposition process going.
The roots will always find their ways, at first around the logs. As things start to decompose, it is first the leaves and the straw that turns into soil. Later the wood chips and the thinner branches. But eventually it's the logs' turn, and yes: Just as you guessed, the roots will make use of those holes and crevices created inside the decomposing logs to reach the nutrients that are being liberated in the process. (To be more exact, before the roots, it is the fungus mycelia around those roots that find their way into the logs, but that's the next step down the rabbit-hole of composting...)