Martmcd's reply is par for someone dealing with normal Microsoft tech. It doesn't consider individual situations. No disrespect intended. I think a little more understanding is necessary.
Yes, it's dangerous if there is any real opportunity for someone else to access your computer, whether it's a Microsoft Community or a local group. But before you go further you have to define in your mind what those two options are. You should think of it as physical people, not as an online set of entities. The Microsoft Community or any other public community, by definition, has the potential for unauthorized actual people to have access to your computer. A local group is ONLY those people that have access to your computer. Understanding that prepares you for deciding to have some level of security at login or not. Remember, this has NOTHING to do with information hacking, viruses, malware, etc, that happens AFTER the computer is turned on.
No, Given the above, my computer is in my bedroom. I'm retired and almost always home. I'm alone. Can you imagine my local group of people (no one) having access actually posing a threat to my computer? Neither can I. For me, and others like me, it's ridiculous to have to deal with logging in, using a PIN or password every time I turn the computer on.