Currently, the Rules button does not appear until a content rule has been created and enabled.
This makes sense in terms of minimalism, but it also makes content rules less visible to inexperienced users and administrators.
In the interest of making this powerful feature more visible and discoverable ("marketing"), the Rules toolbar button should be always visible.
If no content rule exists and/or has not been enabled:
if the user is not authorized to manage content rules, a message should say something like "No content rules have been enabled. To create or apply content rules, contact your site administrator [link to email or contact form]"
if the user is authorized to manage content rules, but no rules exist or have been applied, redirect to the Content Rules control panel
otherwise display the content rules that apply as usual
tkimnguyen
commented
6 years ago 
Currently, the Rules button does not appear until a content rule has been created and enabled.
This makes sense in terms of minimalism, but it also makes content rules less visible to inexperienced users and administrators.
In the interest of making this powerful feature more visible and discoverable ("marketing"), the Rules toolbar button should be always visible.
If no content rule exists and/or has not been enabled:
if the user is not authorized to manage content rules, a message should say something like "No content rules have been enabled. To create or apply content rules, contact your site administrator [link to email or contact form]"
if the user is authorized to manage content rules, but no rules exist or have been applied, redirect to the Content Rules control panel
otherwise display the content rules that apply as usual