Hi @Paulag,
some Steemians have idetified top priorities to set up a marketing strategy for Steem. Maybe this could help you somewhat. The top-priorities they identified are:

Think about consumer attractiveness.
Focus on communities, not rewards in marketing.
Sneak users in.
Facilitate onboarding.

I get the feeling, you're jumping directly onto the third point "sneak users" in. Maybe it would be better to clarify what is your value proposition for yor users first:

Learn by commenting? Or maybe you want to gamify and let them find a bug i your Excel tables and comment this?
SHould they engage with each other on Steem?
Why should they be active on Steem and not on Discord or whereever?

Secondly, why do they need a Steem account?

To earn Steem from the rewards pool? Probably not, @lextenebris already commented on that.
Are there any other rewards in Steem you could offer?
Or could they get your service for a special price when paying in Steem? What is their value for money?

Clarifying these questions would probably help you with the wording. Cause, I have the feeling, you don't have a wording problem.

And final comment: Keep it short. "Sneak them in" and explain details later. First thing should be the value proposition and nothing else - at least these are my thoughts.

Good luck and I'll let you know as soon as we've started to address our first customers.