The main reason is QUALITY. We perform MP3 compression with professional algorithms that are not available in consumer software. Professional MP3 compression provides superior quality. Another reason would be CONVENIENCE.
"I just heard my father's voice 11 years after he passed away. I cannot express my joy enough. He read poems that he wrote and sang his favorite hymn. Your restoration and transfer of an old 8-track made that possible. Thank you is not enough."