What assets we are talking about?
See, there are certain assets that can be only created under any program whereas few assets can be created either in the design studio or under any program in the marketing activities and these assets are:
1. Landing page
3. and Forms
For landing page and emails there is no difference at all. You can create them any of the above place as per your requirement.
Now, the third one is the form. When we create any form under a program in the marketing activities and lead will submit their details through this form, that lead will become the member of this particular program. It simply means if you are using this form in the multiple program then your reporting will be getting affected or you would need to add an extra step in each campaign to assign acquisition program.
If this form was created in the design studio then there is no harm at all because in design studio we don't have anything like program and we can call this form under any program in the marketing activities.
Please let me know if i missed anything.