Custom tumblr url benefits

I have a decently successful tumblr blog. I was searching on expired domains and found an exact match domain within my niche that's pretty much perfect. If I change my tumblr url to this EMD will it benefit me in any way SEO wise or is it best to just leave it be?

The way I see it my content is already there and the EMD would only push it further into SEO goodness. Am I wrong here?

Benefits of custom domain is you can use affiliate links in your blogs but dont spam them. Plus it will help in SEO and its easy to grab link from other tumblr blogs with custom domains.