In Pro Tools, licensing Splice samples does not cost credits depending on your plan:
Splice x Pro Tools
Users with the Splice x Pro Tools plan can license up to 100 samples per day exclusively in Pro Tools without using credits.
Sounds+
Sounds+ users can license sounds in Pro Tools using credits only.
If you're on a Sounds+ plan and wish to license sounds in the DAW without credits, please either switch to the Splice x Pro Tools plan or upgrade to Creator or Creator+: splice.com/plans
Creator & Creator+
Similar to Splice x Pro Tools, Creator and Creator+ users can license up to 100 samples per day in Pro Tools without using credits.
All downloads outside of Pro Tools, such as the Splice Desktop App, website, or mobile app, will require credits.