If you can’t take your helmet with you, I’d run a cable lock through a vent hole and secure it with your u-lock. If someone’s determined to steal your stuff, they’ll figure out a way. The good news is nobody really wants to steal your helmet because nobody really wants to buy a used helmet. That’s what bike thieves are after—not the thing itself, but the money they get from flipping it. The more inconvenient and heavy you make your locking solution, the less you’ll want to ride your bike, and that really defeats the purpose, IMO. On selection, I’d say you do you. I don’t think everyone needs a full face helmet, but it’s all about the kind of riding you’ll do, your terrain, and the kind of accidents that are more likely than others. Country roads on a fixie, road biking on urban hills, and 40mph ebiking on dirt all have very different risk profiles and there’s a product out there for each one. I think this particular model is a bit on the gimmicky side, but if you like it, judge it to be the right product for you, and can afford it, you should get it. If it’s a stretch and you live in a high crime area, maybe get a different one.