Yes your opinion may be useful But also sometimes it may be not useful if such thing occurs..
For example : If you win a Giveaway and u are asked to post your btc address.. or u just have to post ur btc address for some trade purposes and if u post a wrong address by mistake (and u cant edit it ) and the person sends btc to the wrong address then it will create many issues for you.
So sometimes , Editing option is very useful in such cases or might be there are many other cases too.
So i dont think if there is a reason to make such changes in the forum ! )))
If this option is not suitable for specific topic (i.e. giveaway)- then you just don't use it.
In the example you used, you can always make another post with correct BTC address or just pm the topic starter (OP).
I thought of this option when I saw this topic (explain Bitcoin in one sentence.
BTC1 bounty:
https://bitcointalk.org/index.php?topic=1261106.0It's quite easy to abuse. You could create few newbie accounts, reply with anything, wait until someone posts something real good, then just steal their idea (possibly slightly change it) by editing your previous post(s) increasing your chances of winning.
Even if somehow you get caught, just abandon newly created account.