If you are placing the llinks for the sake of traffic there may be minimal benefit since the industries you already have a presence in are not very related. If you have a smilar target market however, the few clicks a month might be worth it. If you already have a method of linking, then what do you have to loose?
From an SEO perspective, the current thought is that links from unrelated sites don’t help you much in the SERPS, though several people have examples where it does help in passing along PR. In the long-run though, it looks like the search engines are trying to reduce the power of links that appear irrelevant. The rule of thumb is “if it is relevant to your users, than it should be relevant for the search engine.”