inner page or separate domain for blog/articles ?

Inner blog on money site OR blog with its own domain pointing to moneysite?

I found that my competitor is having:
1) moneysite.COM
2) moneysite.NET/blog <---this one is for blog/articles only, and its pointing to moneysite

I have:
1)moneysite.COM
2)moneysite.COM/blog <--- same domain, blog/articles i post on inner page of my money site

So what he does is guest posting on related niche sites with a link to his blog which is moneysite.NET

Any ideas what is an idea behind?

I didnt get it but you can simple put a new Wp blog in example.com/blog directory ?

In my opinion, your idea seems simpler and everything revolves around just one website. And I like this better than your competitor's.

I think by doing this, he is taking an extra layer of precaution to shield his main website from any negative link penalty.