Ads can be a malware delivery vehicle.

You assume that modern day browsers are even remotely secure. They still suffer from significant security bugs every now and then. Reducing the amount of third party java script you run is a security improvement.

Fewer requests = fewer potential attack vectors, especially when most of the blocked requests are executable JS code.

Exfiltration of data is a security issue and ads tend to grab any info they can, even if it just loading their ressources. Not a security issue many large tech companies like to focus on for obvious reasons.

You’d be shocked at how many people (smart people included) are fooled by stupid ads and misleading website alerts and notifications. I used to do customer support for a large tech company, and people get sucked into giving up passwords or PII All. The. Time. by convincing ads. Some of these actors even deliberately style the ads to look like system alerts!

Yah, probably not a lot of HN users falling for it, but I was constantly surprised by the demographic. I’d regularly see smart, accomplished people get bamboozled by ads. It’s wild.