Why write and not draw, or make videos or podcasts? There are a few reasons why I choose this format over the others.

Searchable

It's easier to make search engines discover text as compared to video or audio. If you want to look back at what you've produced, it's also easier for creators themselves to search through text archives.

Smaller

Text takes up less space than images or videos or audio. Text size is measured in bytes while the rest of them are measured in MEGAbytes. That's about 1000000x (or a million) more space-saving than the other formats. This makes it easier to disseminate and distribute, especially when internet speed is still a premium or if you're on mobile data. (Granted, the cover photos here will slow that down...)

Easier to create

As compared to images, audio or video, you require less equipment to start with, and it's faster to get from thought to product, just like that. No need for tablets or specialised recording equipment, or learning an entirely new set of tools to produce the content.

Easier to consume

With this medium, it's a lot easier to translate it into different languages, or even different formats for accessibility purposes. It could be easily changed into an audio format, unlike videos or comics.

Makes people think

There were times while reading where I had to pause, and either re-read what I just read, or think about what I just read. It requires a little bit more brainpower and the progression is controlled by the reader; thus we can take as long as we need to absorb the content.

Why NOT text?

Not as engaging

Video wins hands-down in terms of getting people absorbed in it. Though you may argue that text engages people differently - you think about the content instead of just consuming it. I know some people who spend a lot of time consuming video as their primary form of entertainment and primary form of learning. Some people have difficulty reading, too, due to a lower attention span, dyslexia or other obstacles, and may strongly prefer other mediums.

Depends on skillset

If you are not good at language or really hate writing, then don't write! Sometimes you may be more inclined to a different medium.

Cannot multitask

It's way easier to multi-task with video or podcasts as compared to reading an actual book, say while driving or cooking. This could reduce your productivity.

Conclusion

I personally would stick with text for myself since I like writing and also want to get the other benefits of text that can't be found anywhere else. However, I would also experiment with other mediums, since I find it fun and the generalist in me cannot resist. Some things are really better said through other forms, too.