As someone else put it, it's for making sure your wife doesn't get suspicious of the weird ads you're getting, and when she checks the browser history it's clean.
Meanwhile Google, your ISP, and the NSA all know you're looking at freaky old lady bondage porn.
Considering the amount of scandals around government services I'd rather trust your ISP. Also your ISP won't put you in jail for watching weird porn if you go to a protest.
Except some sites seem to use your IP, so if you're both using the same WiFi, you're going to get ads for other party. And for anyone else who used the same WiFi, too
It's handy when you need to make sure that someone else can access a url ok without having to sign in to the website or anything. If you can immediately see the page in incognito mode without signing in, they'll have no problem
I remember having to use an incognito browser for testing at work one time, and it felt very wrong to pull it up on my work laptop instead of the personal laptop.
That's a good trouble-shooting step, but it's not a solution. That's some bullshit, sorry that happened. Maybe try clearing your browser cache and cookies if you haven't already? Basically my reasoning is if it works in incognito mode and only in that mode, then there's probably some saved state that the website is getting snagged on (state that a new incognito window wouldn't have).
Websites with actual web devs block and track usage with ip instead of cookies/cache, nothing a vpn can't stop tho. More reliable to is to the way back machine on archive.org. Can also use a browsers reader mode to get around it too sometimes.
back in the day (before chrome or incognito mode) I used to manually delete specific history items, individual cookies and temporary internet files one by one to leave no trace, while not making anything look suspicious, all so my nosy brother wouldn't stumble on any evidence and use it to mock me