Historically people exposed to loud noises had very few choices in hearing protection. There were the large ear muffs that went over the ear and non-custom fit earplugs.
More recently ear protection has been designed for shooters allowing the shooter to still hear people talking while being protected from sudden loud gun blasts. While these electronic earplugs were initially designed for shooters such earplugs are often useful to people working in noisy environments who still must hear people talking to them.