Yes, it is more than good enough. I use it on all my systems, including those used by the older grandkids and other guests - that is, by people with less "security awareness" or discipline than me.
More important than, and regardless which security solution you use, is the need to keep it and Windows current, and to avoid being "click-happy" on unsolicited links, downloads, attachments and popups. Also, as suggested by WatEagle, it is a good idea to have a second scanner on hand, just to make sure you (the user and ALWAYS weakest link in security) or your primary scanner did not let something slip by. But note that is regardless your primary security solution of choice.
I think it is important to remember that Microsoft does not want our systems to get infected. They know if that happens, the IT press and anti-Microsoft bloggers and other bashers will be relentless in their criticisms on Microsoft and W10. If for no other reason, that sort of bad publicity is just bad, very bad for business.
It's fine as long as you use common sense
I agree 100%. But again, that same advice applies to which ever security solution you use. None are 100% perfect 100% of the time, and that is particularly true if the user is careless, carefree, partakes in risky/illegal behavior, and is click-happy on every link they see. The best security in the world is pointless if the user opens the door and lets the bad buy in.