Do I need bitdefender

I’ve read that bitdefender is a very good anti virus for iMac. However, do I need it? I will use my iMac for working from home. I wont be linked to any external computers. However, I will sometimes need to connect to web servers and my own website to make alterations to it. I need to connect a printer to it which will require a software download. I will need to use Microsoft office on it and send and open documents to and from people and organisations with Microsoft software. What do you guys think? Any advice would be appreciated. Thanks in advance.