I wasn't, sorry if I was confusing. My point was that the logic "I can imagine that it may be worth doing X even if there is a cost Y, so it must be worth it"

I wasn't, sorry if I was confusing. My point was that the logic "I can imagine that it may be worth doing X even if there is a cost Y, so it must be worth it" is wrong. If it may be worth it, it means that you need to investigate.