Absolutely nothing. You can learn everything you need to know about this topic from AI and save $2,000/month

• The original concept made sense for technical teams: own the stack, control IPs and domains, and avoid per‑message fees with a self‑hosted sending pipeline that promised flexibility and brand control. • Early on, the positioning around privacy, white‑labeling, and integration with external SMTP/API providers sounded practical for agencies and high‑volume senders who want autonomy. • The architecture idea, on paper, fit advanced deliverability workflows like domain segregation, sending warmup, and routing options without being tied to a single SaaS vendor.

Good idea, that's about it!!! I haven't really got anything positive to say about it as the problems have overshadowed any positives.