Sure but not at the expense of hours & experience imo. Get the core time first, then build on that. Time as a CA is valuable, both for professional enrichment and for points on an app. Being a ground instructor doesn't come close to that- its just not where you build *in flight* decision making, leadership, interpersonal skills, crm, customer service skills, etc etc. And those skills are built better on the line vs in the training dept, and I've done both fwiw.