SAM and the SBA dynamic small business profile are effectively the government's Google. When officials need something, they do not search the open web — they search these registered-vendor systems and contact businesses listed there.
Two consequences follow:
You cannot be paid without them. Agencies pay through the system by direct deposit, so even a highly capable business cannot be hired if it is not registered.
Being findable drives inbound work. A complete, well-keyworded profile is what generates direct calls for smaller purchases and sole-source outreach, separate from any formal RFP process.
Think of profile setup like search engine optimization: your primary NAICS codes, keywords, and capability statement have to be set up properly so you appear for the right opportunities. A key rule taught in the program is to neither over-qualify nor under-qualify your business in how you present it — your profile should match what you can genuinely deliver.
Note that SAM registration takes real time, typically around six to eight weeks, which is why it is treated as the first priority after your entity is in place.