Hello,

For commercial purposes, it depends on how you will use the data. You should :
_ Check the local law, it differs between countries.
_ Selectively choose which data to use. There are lots of sites providing similar information and they are also collecting data from many sources somehow. In addition, if you simply clone everything to make a site as same as the official one, you will violate DMCA policy
_ Have data wrapped in another service.

For example,
There are users using our financial API as a feeding source for their AI bots, the bots store and use data to analyze and speculate stock investment trends.
There are users collecting house prices for their own pricing estimating tool.
Google search engine and its advertising business is also another good example, the engine crawls data from sites first for its business.
Remember that you are not allowed to use the branding or trademark. You will be forced to take it down in the future when your site/application becomes famous.

Regards.