I thought I'd reply because I've been thinking about this a lot and have reached my own conclusion.
I think that the key consideration is who your website is aimed at and what languages they speak. If you work only with English speakers and have no desire to work for direct clients then it probably isn't worth having a multi-language website.
I also translate into English (from Italian), and I am a copywriter. I currently work with Italian clients but they are based in the UK and we tend to communicate in English, however I do plan to target Italian clients. I think that before I do that, it will be important to create an Italian version of my website. It will look more professional, and also show the clients that I care about them if I communicate with them in their native language. Also making sure it is SEO optimised might make it easier for clients to find me through Google search.
However, I am going to concentrate on getting my English website up and running first, and then add the Italian one in further down the line. The reason is that I am going to get an Italian copywriter to write the Italian version, so that I can ensure it has the right 'punch' in Italian as it does in English, to give Italian clients a taste of what my writing is like, but in English. So that will take time as I will have to pay for it.
Of course that may seem a bit extreme, and is mostly because I am working in the marketing/ copy sectors. If I worked in a more technical field, or e.g. legal, then I'd probably write it myself and get a native to review it, or get a native Italian translator to translate it.
One thing that I sometimes see is websites of X language to English translators that have obviously not been proofread by a native English speaker, and I think it really undermines their credibility.
Hope my two cents help!