I’m running forum.csclub.co.
csclub.co redirect to
forum.csclub.co (I will remove this redirect as soon as I install WordPress at
csclub.co) and there are domains and expired domain that I have bought for redirecting to the main site.
Is it good practice or it just that work on your main domain and make it brand and do not worry buying an expired domains or domains (of course domains are related to my niche) to redirect to the main site to get some traffic and also making sure other should not buy these domains.