I think the choice of wording here is slightly unfortunate. ALL aviation training is worthwhile, even if you don't use it directly. To take an example, as some of you know I've been intermittently learning to fly a flexwing microlight, damaged my shoulder on a less-than-perfect landing, and have put the whole thing on indefinite hold. But I learned a huge amount about weather and aircraft responses, flying non-radio, and other stuff that I hadn't known before - all of it useful no matter what you fly. Perhaps more directly related, the few hours of instrument flying that I did for my CPL(H) has been very helpful when flying either helos or f/w aircraft in poor visibility or over water, where you need to use the instruments more than usual. I haven't done an IMC - been trying to fit it in for the last four years - but I plan to someday.
Now as to whether you should do it if you don't have the time and money, or would rather spend them on something else; that's a different question and comes down to priorities.