The GSM mobile telecommunications standard serves approximately 80% of the global mobile market, encompassing more than 5 billion people across more than 212 countries and territories, making GSM the most ubiquitous of the many standards for cellular networks.
Much like the metric system, the US's failure to only utilize the GSM standard leaves us behind and costs technology providers and manufacturers (and thus wireless consumers) billions.
Individuals who require cellular or mobile internet services travel abroad require complicated, expensive, and potentially shady transactions that involve buying new equipment such prepaid phones or sim cards from other countries, unlocking phones, or buying prepaid phone cards that are often scams.