Yes, both the actual skills are much better than nothing, and much more importantly, getting used to getting hit is very, very important. In the real world you’re going to get hit. It’s going to hurt. You’ll probably bleed. You need to be ready for that.
There are downsides, but again, if you’re talking about a normal person, willing to spend maybe 1-6 months to learn to fight a little, then boxing is great because it involves high contact and pain. The fear and shock from getting actually hit by someone, especially a female if it’s the first time she’s actually felt the strength and power that an adult male has, is the best thing that a criminal has going for them.
As far as offensively, I prefer the simple stuff, grab any body part you can and try and take a chunk out with your teeth. That will likely dissuade most actual attackers (in addition to actually really hurting the body part, despite the fact that you won’t actually tear a piece off, you will do damage to the underlying tissue and will reduce the utility/effectiveness of that body part), the human teeth are incredibly strong regardless of your size, and are a vicious weapon.
You need to be very, very motivated to be willing to get too close to someone who is hell bent on grabbing whatever they can on you and biting as hard as possible.
Most criminals are nowhere near that motivated.
Note this advice is not for looking cool outside of a bar when somebody is talking smack, this is for a situation where your life is in serious threat (the only time should ever risk fighting).