Is it bad that I let my kids eat cereal for dinner sometimes?

Okay, real talk. Sometimes after a particularly brutal day with work and kids, I'll just let them eat a bowl of cereal for dinner instead of actually cooking something. My wife gives me this look like I'm poisoning them but like... cereal has milk, right? That's calcium. I'm not doing it every night, maybe once a week max, but is this something I should feel guilty about or am I overthinking it?