Highlight your technical skills and focus
If you're applying for a technical role like an ETL Developer, it's crucial to talk about your specific technical skills. In this case, focusing on performance optimization and data integrity shows that you understand what matters in ETL jobs and that you've got what it takes to deliver.
Talk about your previous companies
By mentioning your experience at well-regarded companies like IBM and Microsoft, you're signaling a level of competence and adherence to industry standards that can be very attractive to hiring managers. It's a shorthand way to say "I've been trusted with serious work before".