The ability to send secure messages from one person or device, without having access to another's keys is great! It can be cumbersome for people that are not very tech savvy but it all comes down to how much you want security vs ease of use/usability when choosing this product over other options available in our industry (e-mail encryption).
I would recommend trying out their free trial before purchasing if your unsure what features will work best with your business needs. We have been using them as an e2E solution between multiple employees at my workplace; however we also utilize encrypted email solutions via PGP so there was no need to replace any existing services used by these products.