Well, it depends what your goals are. I write full-time and earn a full-time income, so I don't have the luxury of only writing about topics I love. I've been doing this for a while, so I can focus on subjects I'm interested in (for example, the tribal article on my signature). However, I also write articles on topics like floor materials and real estate, which are not necessarily interesting to me.

I don't write for content sites anymore, but I used to when I was just starting and needed quick money. That's what content sites are for: to make quick money. If you're spending anything more than 30-60 minutes in an article for a content site, you're overwriting. Writing content or SEO articles is not about what interests you. It's about earnings, just like any other job: you write for the money, not for the love of the subject you're writing about.

If you write more for fun/personal satisfaction than money, then you can choose what to write about. Otherwise, you might need to write about topics you don't necessarily love while you're trying to build a portfolio.

By the way, having a blog could be a good thing, but I don't think it means much when it comes to impressing an editor. After all, it's your blog, so everything you write is "accepted." I think it's better to try and sell some pieces somewhere else. Are content sites good for clips? Well, yes and no. Actually, no, but if you have nothing else, you can try publishing a few really good-quality, well-researched pieces so you can refer editors to them. However, if your goal is not to make money, but to focus on writing what you love, content sites don't make a lot of sense.