Dynamic Forms:
We can show/hide fields/sections based on filter criteria
cutdown on number of pagelayouts by having single dynamic form with set visibility for different profiles.
You can also display fields based on values in fields on parent object.
For sales and support you want to display different set of fields and sections altogether.
You can add filters to field sections.
Field visibility is applied even before saving a record.
Dynamic Actions:
Helps to control visibility of lightning actions on lightning page
Here you need to save a record to apply record level filter.
"Remove as Org Default" would disable dynamic forms and would display page layouts.
Instead of setting as org default, You can select app, recordtype, profile to selectively enable dynamic forms for some users.
