There are several benefits of using a soft-attach blocks. Ultimately rope attachments can be kinder to your boat and surrounding hardware, they can also provide better load balance than a shackle. This means your block will be subjected to the load being pulled through it at an preferential angle, reducing the risk of breakage, and minimizing space taken up on deck.
There will be some situations where using soft attach blocks is not as suitable; for instance if the rope attachments are going around a rough edged surface then the rope can be more susceptible to wear and chafe. It is worth regularly inspecting the rope more often to look for any signs of wear. It is also vitally important to ensure the block is installed correctly so as not to compromise the function of the block.