This would definitely be a good way to help declutter the discord channel. However, it might be a good idea to keep the older posts within the forums still. If the discord posts are autogenerated by the posts made in the Feature Requests section of the Forums, there could be some sort of bot or script that automatically moves the post to a sub-section (something like "Archived Feature Requests"). This way the discord channel posts will be removed but the actual forum posts will still be preserved.
Depending on the nature of your question, the response you recieved is not necessarily accurate. Like Yacob stated above, that channel is actually meant for players to ask staff about non-urgent topics. If you were asking about some aspect of the Expanse server (how it works, ranks, shops, maybe plugin functionality, etc.) then that would be completely valid. Was it a Mod/Helper that responded with that response or was that a normal player?