Manure "burn your plants". Here's why. Fresh manure is full of waste organics, but it requires further "processing" (composting) by decay micro-organisms that really "gobble up" all that raw material by multiplying and growing. After a while they use up all that raw material and die off, releasing it in a plant-usable form. But while they are growing and using, they ALSO need a bunch of other nutrients they take from the soil, especially nitrogen (and oxygen from the air). So that means there is a real DEFICIENCY of those nutrients in the soil until the rotting process finishes and those things are part of what is released as the micro-organisms die off. THEN all the nutrients are available for plants. (Side bonus: this process destroys all the stinky parts of the raw manure.) Almost nobody sells in bags raw manure before this composting process - raw manure normally can be obtained direct from a farm producer, but not used immediately.
All composted manure has low levels of NPK. It's cheap and you use more of it in your soil to get enough nutrients into the soil. The claim is that it also carries other nutrients in trace amounts plus some of those normal soil micro-organisms, as opposed to pure chemical fertilizers with a limited number of ingredients. That particular product is NOT just composted manure. It is also blended with other scrap organic material that can add looseness and air spaces to dense soils and will be slowly degraded in a similar fashion once mixed into your soil. But that's a slow process. Really, it is there as cheap "filler" to keep the overall price of the mixture real low and appealing until you realize that you will need to use a LOT of it to get any real boost to your soil's health.