If you're a business
Google maps can help get you noticed as a branded business and give your website a push as the Google map link very powerful.
But there a downside google maps not free no more the more clicks you get the more you pay or the more someone uses the map under your business the more you pay.
But the advertising side it used heavily to gain business in areas.
Just be careful if someone crawls to you, they can send heavy traffic to your map and that will burn your map credit and you can get huge bills.
It does cost but every month you get free credit but run low quick.
To join you usually get sent a pin thu your business address and that activated the account.
That it once the account open and you describe your business you just keep the phone number updated.
I am sure their methods to be top on the list and stuff like that.
I am sure you get an API when joined to slap in a theme WordPress for your website. ( just a square map indicating your business on your website.
I think that what increases the height in Google for your website. (( what you m8 was on about))
Be careful when you join you add your business info and credit card or bank info, the map billing has no limit so the more busy the map is the more your pay for credit monthly it all auto.