Is 'alt' an important tag to use in web pages, can it be avoided?

Alternative text provides a textual alternative to non-text content in web pages.
Alt text represents an image in any situation where it can’t be seen or displayed.This includes:   - A person using a screen reader who can’t see the image.
- A search engine scanning a page’s content.
- An email client that has blocked the loading of images.
- A broken image.Adding alternative text for images is the first principle of web accessibility.
ALT in a Days Work! Along with headings, alt text is one of the easiest-to-implement accessibility features, and it doesn’t take that much time. 
If you build it into your workflow, then it takes almost no time. 
If you have skipped over it in the past, it will take a while to go back and enter it on each image, but it still won’t take long.
And remember, for a little work, there’s a big payoff: - Your website can reach more people.- Your website communicates more effectively.
- Search engines understand your website better.

ALT tags provide a text alternative to an image They are a way to "describe" an image to those who can not see the image.
The most important function of an ALT tag is to explain to a blind user what an image is displaying.
Search engine crawlers also use ALT tags to decipher what an image is or what it is representing.
It can be avoided but it is not a proper way to develop a web page

I agree with all answers mention above but 'alt' html tag also very important if you want website to be SEO optimised and compatible across platforms.
Our search engines smartly search for images from website through alt tag and also allow text base description of image if bandwidth down.
So avoiding alt tag is bad practise.

Guys it is also important when we validate the websites html code, if alt is not defined it is measured as error.....thanks for answering you answer indeed is accurate.....

The required alt attribute specifies an alternate text for an image, if the image cannot be displayed.
The alt attribute provides alternative information for an image if a user for some reason cannot view it (because of slow connection, an error in the src attribute, or if the user uses a screen reader).
Better to use it rather than avoiding.
Avoiding will not make any specific errors