Landing pages, standalone, one page websites, are ideal for certain purposes, however, misused, they can result in Google penalizing your website.
SEM
If you're running search engine marketing (SEM) campaigns landing pages are invaluable. When an individual clicks on your ad, you want them to convert since you are paying for each click. Landing pages offer consumers all the information that they need to make a purchasing decision, without anything else to distract them. If you link your ad to the product's page, the person will have to click to read your shipping policies and possibly click again to see what forms of payment that you accept. Somewhere in all this clicking, consumers tend to get frustrated, especially if they are on a smartphone.
Link Farms
Link farms are just one of the tactics used by unethical SEO firms to increase their client's backlinks. The tactic often results in a Google penalty, but the company already has their money. Link farms consist of a group of websites, usually one page sites, that all link bank to the money site. There are some business owners who have extra domains and decide to do this on their own, without realizing that instead of helping them in the SERPs, it actually hurts them.
Major corporations that don't want others pretending that they are affiliated the company will buy every domain name with their business name in it. If you're worried that this could happen to your company, keep the domains and redirect them to your main website. You run the risk that people who land on one domain that redirects to another will believe something is fishy.
If you have extra domains for your business, use them for SEM purposes, not SEO. You want to concentrate on creating the best content possible for your main website. Use the extra domains for ad purposes, learning all about landing page best practices first.For more information click here https://www.reddit.com/r/SEO/comments/89nk7f/doesalandingpagebringseoadvantageto_a/.