I get this question from people this can often stall your efforts. You have a message and you want to get it out there, but what format?
As a content creator (and when you boil it down, that is what podcasters are) what do you want? You want more exposure for your content. So why limit yourself to one type of format?
Video Can Be Easy
You can use Facebook Live or YouTube Live (formerly Google Hangouts) for free. Every morning I stream to YouTube using StreamYard (for some added features of pulling people into the chat and some cool display tricks) and record the audio on a portable recorder. While the audio on Facebook, YouTUbe and Zoom are tolerable, try to record it locally was a WAV file to capture the best audio you can.
Things to Avoid When Multipurposing
Try not to say things like “As you see here” as the people who listen to your audio later have no idea what you're talking about.
Two Formats – Two Editing Sessions
When you produce to formats (audio and video) this means you get to edit both versions. This just takes more time.
If You Have To Choose One Format?
Unless you are doing something like a cooking show (that REALLY needs the visual) go with the audio.
It's cheaper to host
It's easier to edit.
You don't have to shower or put on makeup to record.