1/ Investors (equity and credit alike) love contractual, recurring revenues thinking it protects them because the customer is legally obligated to pay. That forward revenue visibility makes it very easy to model and value in theory.

2/ At the end of the day, you're still underwriting the credit risk of the underlying customer and its product/sales/demand. In times of crises, existing arrangements get renegotiated. Everyone feels the pain.

3/ I see this mistake most often when investors overpay or assume a multiple re-rate for "stable" companies such as REITs, MLPs, and other financing companies (e.g., aircraft lessors like $AER).