So, the normal approach to web coding is to essentially lay out your page with a classic header, body, footer approach, staying true to all those parts and then stuffing the content in various forms, layouts or frames in the middle. It's been a traditional approach used for decades now, and the boring style is obvious. It's also very work intensive.

Granted, some aspects of web coding can be boosted with CSS, which essentially references a style external file at the beginning of the web script or brings it in directly in the various parts of the body. It's generally easier to reference the external file and control everything from one or two CSS files, especially when you have a home page portal and then a bunch of subpages that you want to look the same in style and appearance. 

However, if you don't have time to cook up a new site from scratch, but you want something that is easy to navigate, easy to modify, and most importantly, adjusts quickly to the device that people are using to view the website, a Bootstrap template can be a very handy tool. Rather than having to figure out all the different sections in the HTML and then style them with the related CSS, you simply inject through linking the classic Boostrap look, and most of the work is already done for you. You can then focus on content versus spending hours and hours getting the styling right, especially when you're building the site for someone else. 

How does Bootstrap work? See the two snippets above for reference.

By referencing the related CSS and Javascript, your page shell is created automatically. All you then need to do is fiddle with the colors and material as well as the images in terms of how you want them. In fact, if you want to go even faster, you can simply tell an AI engine to create a bootstrap page for you with the key elements, and the work is kicked out and ready to load in a browser in less than a minute. Pretty snappy!