Yeah places like Swan are really awesome and provide a great service, I think. The problem is there are two major reasons companies use services like Prime Trust.

1.) Resources. They built up tooling and provide good starting point if you have minimal resources or capital as a startup.

2.) This one may be a bigger reason. Offloading these things to a provider also offloads legal responsibility for your business. Prime Trust is responsible for storing and securing that data. Should a breach happen Swan is not on the hook for it.

You should do your DD on Prime Trust though. They nearly have a monopoly.