A portfolio is crucial for several reasons:

Showcase Your Skills: It's a visual representation of your abilities and accomplishments.

You can present your best work, demonstrating your expertise and problem-solving skills.  
Differentiate Yourself: In a competitive job market, a portfolio can help you stand out from other candidates. It provides tangible evidence of your skills and experience.  
Build Credibility: A well-curated portfolio establishes your credibility and professionalism. It shows potential employers that you're capable and competent.  
Land Job Opportunities: Many employers require or prefer portfolios, especially in creative fields. It's a valuable tool for securing interviews and landing jobs.  
Track Progress: A portfolio can serve as a record of your growth and development. You can see how your skills have evolved over time.  
Networking: Portfolios can be a conversation starter at networking events. They provide a tangible way to introduce yourself and your work.