Global assets are much better. Local forms make the net new lead as acquired by and any lead as a member of the Program automatically. That's usually ok, but I prefer to control that more with standard forms and status flows.
You should have several Standard Forms:
Content Download
Email Newsletter Sign Up
Unsubscribe or Subscription Management
Webinar Registration
Event Registration
etc
This ensures consistency of data collection, especially if you are using Hidden fields or URL parameters to stamp leads with more data.
Yes, you can CLONE these standard ones to a Local Program, but do this sparingly.
Please remember that the Fills Out Form trigger has a valuable Constraint: Web Page. So your new form trigger will be
Fills Out Form IS "Standard X" on Page "Y" to ensure you collect the person on the correct Program.