So can you use drywall tape and compound to make larger plaster wall repairs? Yes you can although some caution is required. Whether it is plaster or drywall, the main purpose is for it to hold up the paint. A smooth plaster surface or a smooth drywall surface will both to the job. Drywall compound will stick to plaster and drywall tape will bridge gaps and smaller holes. The moral to this story is that drywall materials will work for plaster repairs as long as they are not too severe.
Using drywall mud and tape does require some skill and practice. See the articles 'How To Patch Drywall' and 'Taping and Mudding Drywall' for pointers and information on using drywall materials to repair walls and ceilings.
Drywall materials are easier to obtain, they are readily available at home supply stores. Plaster materials are more difficult to obtain. You have to go drywall or masonry suppliers to obtain them. You also need a lot more practice to master these skills. Where possible, the course of wisdom is to try and use drywall products for plaster wall repairs.