If you’re on about pointing it to an already existing site that already has a primary domain name then no it’s a pointless feat… there are some benefits setting up a site with keywords embedded as long as that domain is the primary domain…
The most obvious ones being a slight boost in the match for the raw search but there are visual differences too.. keywords / phrases are bolded in the results which helps them pop from the page a little more. I wouldn’t be scared to use hyphens to help the word clarity of that “popping” either.
The site needs good quality content with over 500 well written none copy and pasted words… good site structure, fast loading and ideally https.
You’ll want to try and get other high quality or relevant sites to link to it too.. backlinks is another story though but basically nothing quick and cheap.. dont buy them and don’t try to cheat the process.
If you make a useful site thats relevant and well built then the recommendation engine we know as google will reward you… there is also a reason why good web designers get paid well and it’s not because these things are easily learnt you’re first time round.
Edit.. just seen the post above.. if you do a 301 of the existing site… assuming the primary domain has value or time served then 301 is the right approach.. however you’ll be best being careful with your assessment of the current site and if it’s worth redirecting any links from that to the new domain