By staying with Magento 1, you not only risk customer data, but you also lose your competitive edge because new features and innovations will only come out for Magento 2.
Magento 2 delivers a modern, scalable ecommerce solution for businesses of all sizes, and it offers unmatched flexibility and customizations. Compared to Magento 1, Magento 2 can process more orders per hour on the same hardware with faster server response times, which provides customers with a stress-free experience. Check this blog for more info https://elogic.co/blog/magento-1-to-magento-2-migration-guide/