AFR gauge with o2 sensor worth it or not?

Will be finishing up my engine work in the next week. I purchased the header reducer with a O2 bung in it, just in case. But wanted to find out what the general consensus was on spending the $200 on a wideband set up for a mild 318. I live at 7000 feet and can drop down to 5500 in a 30 minute drive. So I am never sure if I am too lean or rich, edelbrock 1405@8% lean with new rods and jets. Reading spark plugs good enough for just a simple street engine?

Let me know your thoughts! Worth it or not?