I think it's important for Harris to do Rogan, huge audience and a chance to speak to the margins. Joe is a bit dumb but he's not mean spirited, he won't come at her unprofessionally. 3 hours on Rogan is honestly a massive opportunity for her to shine, if she's up for it.
The problem the left faces is certain spaces are "off limit", she will be heavily criticized for going simply based on the public perception of Joe and his previous content. IMO this is where Trump has run a much better campaign than her, he's pushed the envelope to reach larger audiences.
I hope she does it, I think she'll be great, hope the overly sensitive portion of our party doesn't grill her for it.