Something bothered me about this post and it took me half the day to figure it out.
Now I know. Writing a bio, getting an author photo taken, cleaning up my website. These are all things my poor little woodland creature brain thought a marketing department would help with.
Having (not a ton I realized, but at least some, I thought) support from a marketing department was on my list of Traditional Publishing Pros.
You will get help from the marketing department if the publisher has one. Smaller publishers often have only The Publisher wearing many hats.
Larger publishers on the other hand do have marketing departments and they publish 750 books a year. They can't focus on the small stuff or they won't be able to do the big stuff.
Author photos, cleaning up your website, and writing a bio IS small stuff. It's stuff you should do before you even query.
The marketing department at a big publisher is going to pitch your book to Barnes and Noble, and Walmart and make sure their own website has you listed correctly, complete with a high-res image of your book cover among many other things.
Getting YOUR web presence in order, that's your job.
Here's how you can tell what to do and what to leave to a publisher: do you know you need it done? Can you do it, or hire it done? Yes? Yes? Do it.
You aren't able to get a meeting with the Barnes and Noble fiction buyer, so leave that to the publisher.
And don't confuse promotion with marketing. Promotion is making sure people know about the book. Marketing is making sure people can buy it. You'll be doing most of your own promotion on a debut novel no matter where you're published. I hope you won't be doing most of your marketing.