Why Base64 Encoding Exists
Base64 exists because many older systems and protocols — like email — were built to reliably carry only plain text, not arbitrary binary data, so Base64 converts any binary data (like an image or file) into a safe set of 64 printable text characters that any text-only channel can transmit without corruption, at the cost of increasing the data's size by roughly a third.
This origin in early text-only email systems is why Base64 remains common today even though most modern channels can technically handle raw binary data directly.
The specific problem it solves
Raw binary data can contain byte sequences that older text-based systems misinterpret as control characters or formatting instructions rather than actual content, corrupting the data in transit — Base64 sidesteps this entirely by re-encoding everything into a restricted set of safe letters, numbers, and a couple of symbols that every text system handles correctly.
Why it's still used in modern contexts like JSON
JSON, a widely used modern data format, only supports text values, not raw binary — so embedding an image or file directly inside a JSON payload (rather than referencing it by a separate URL) still requires Base64-encoding it first, which is why the format persists well beyond its original email-era purpose.