Question normal

Hi all. Thank you for the forum! I am a cardiac sonographer interested in learning more about POCUS and eFAST exams, and have a couple questions:
1. What is the benefits of a lung ultrasound compared to conventional clinical methods of assessing a patient (e.g., chest x-ray, physical exam)? In other words, if you have more clinicians at the point-of-care who are able to perform a lung ultrasound, how does that benefit the patient and the institution? 
2. When you are thinking about the cardiac views to scan on a patient, how do you decide what views to scan? Is it based on the symptoms the patient has or the assessments you are looking to scan or a pre-determined protocol?
3. Do clinicians at the point-of-care use color doppler functionality and / or caliper measurements?
Thank you for your time and expertise!