Photoshop is a tool just like any. It's not necessarily right or wrong - it just is. There might be better tools or worse tools.
You need to ask:
Can I achieve the necessary result using Photoshop? Will the file be in the correct format and below size restrictions for any other parties involved?
If No to either one, then it's an inappropriate tool. However, it needs to be stressed this has absolutely nothing to do with whether or not its the best tool. That wasn't the question. This is only a statement of when it is not the correct tool.
Some examples:
CV / Résumé
Could work, but too often do you need to send your résumé as a .doc to upload for an automatic reader. A work-around (which is a good idea anyways) is to have two résumés. One specifically for upload purposes in plain text and one that can be styled however you want. If you want to make that "styled" one in Photoshop - fine. In Word - fine. In MS Paint - fine. etc...
Posters
It can be done depending on how you're printing and what you're putting on it. You and/or any sort of file transfer that needs to occur could run into memory issues if it gets very large. Again Photoshop might fail to meet size requirements though you could probably do an entire design in it easy enough. If you're just printing something on a plotter in a university lab it should do just fine though.
Logos
While its certainly not the best tool it can absolutely be done, saved into any format you need, and scaled relatively easily especially if you start with something at a decent resolution. Again, this doesn't mean its the best tool - it just means its not an incorrect tool.
My personal workflow for print ads:
Photoshop is what I know best. I do almost everything in Photoshop and then scrape the images out and recreate the entire thing in InDesign. But I do the whole thing entirely in Photoshop first. Just retype it and rebuild vectors in InDesign / Illustrator after because of how much better the quality will be and how much smaller the files will be. I've certainly been lazy at times or hit deadlines and had to submit straight from Photoshop. Likewise I've met MANY a graphic designer that doesn't know or touch InDesign so will send a final ad from Photoshop over. Is it wrong? No. Is there better? Yes.