I have never trusted links that use URL shorteners, and have never clicked on them when I have come across them, which probably shows what a suspicious/paranoid luddite I am. Is the problem of very long links so bad/common that they warrant keeping the potential vulnerability?
I think that unless a person is extremely disciplined, it is difficult to be confident of not clicking on any link on a forum without first hovering the cursor over it to check the web address. I maintain that level of self-discipline with emails, but that is much easier to do, since even where emails from apparently trusted senders contain links it is usually possible to type the web address manually into the browser or to find the website via google.
It is different with an internet forum, because much of the content is naturally engaging and interesting, and so it is much easier to be absorbed when reading a post and unthinkingly click on a link in it. A link that looks
exactly like a safe familiar web address will catch some people out.
viewtopic.php?f=15&t=145078
https://www.parktool.com/blog/repair-help/bottom-bracket-service-adjustable-cup-and-cone
https://www.spacycles.co.uk/m14b0s123p409/SCHWALBE-Inner-Tubes
https://www.wiggle.co.uk/shimano-acera-m360-rear-mech-78-speed
As for whether the benefits outweigh the disadvantages, that is inevitably a somewhat subjective judgement: anyone who gets caught out by a malicious link will have a different perspective.