There’s more to UX than mockups and prototypes.
Affinity Diagramming
Analytics
Card Sorting
Content Inventory & Audits
Design Studios
Diary Studies
Discovery Research
Field Testing
Focus Groups
Heatmaps
Journey Maps
Market Research
Mental Models
Personas
Product Principles
Scenarios
Sitemaps
Story Mapping
Storyboards
Surveys
User Flows
Animated Prototypes
Code Prototypes
Element Collages
High-Fidelity Prototypes
Low-Fidelity Prototypes
Mockups
Mood Boards
Paper Prototypes
Pattern Libraries
Sketching
Style Guides
Style Tiles
Wireframes
A/B Testing
Design Critiques
Guerilla Testing
Heuristic Evaluations
Lab Testing
Remote Testing
A high fidelity prototype gives a close facsimile of the production version. It can feel real to users you test with, many clients or stakeholders are more comfortable with it, and it can serve as a starting point for developers to build from.