There is one main advantage and there are several disadvantages to Free Websites.
The main advantage is price. They are free.
There are several disadvantages to Free websites.
Your website will have the name of the Free host included.
Often the owners of the sites will change their terms and eliminate your commercial sites. The owners are often against anyone making money.
Even simple adsense ads often cannot be added to your free websites. See Wordpress free Sites.
Even many of the Big Free sites have
While Wordpress offers free webhosting it has changed a lot through the years. When I first started using their free hosting several years ago, you could put affiliate links on your site. I believe you could even use Adsense, however I am not certain on that point. Now they close down any free site that is remotely commercial. They do allow and promote use of the Wordpress blog and website builder on your own web hosting. I believe that Wordpress sites are the fastest growing format used for building websites. I know it is very easy. I have given up on using their free hosting however.
I have built several successful Google Free websites. By successful I mean sites that make money. I have some affiliate links on them and I have Google Adsense on all the pages. Some of my Google Sites I had when it was GooglePages and they were converted to Google Sites. I have a couple that are making over $100 per month. Google limits the number of sites you can build. It is not clear what the limits are, I just know they will not allow me to start any new sites at this time. I have about 15 different Google Sites free websites. I really like their site building interface.
Blogger blogs used to be great for promoting other websites and affiliate programs. They limit what you can promote and will cancel your blog if you have too many affiliate links, advertizing or whatever. Their terms of service are not very clear and if they close one of your blogs they will not respond to questions, and you cannot retrieve your content.
I will not spend much energy building pages on free websites. The terms change and the companies go out of business. If you cannot figure out how the owner of the Free site can make money then they probably won't be around. Google sites and Blogger allow Adsense which makes both you and Google money. Wordpress is a huge community website building developer and will be around. Many of the other "Free Web Hosts" will just disappear.
In my opinion it will be most profitable for you to put your energy into building more pages and value into your own websites. I will use free hosting to build some links to some of my sites but I will not build websites on free hosting I am trying to make money with. Build your money sites on domains you own.