...with relying on a weapon to feel secure is that you're pretty much screwed if taken off guard (which you will be if you get overconfident because you have a weapon on you) or if your weapon is not immediately to hand.
No amount of weapons are going to help you if you feel "6 feet tall and 250 pounds" by virtue of having a weapon on you. No one who harbours that attitude should be allowed a weapon. PERIOD.
Feeling "6 feet tall and 250 pounds" is a recipe for disaster under any circumstances. Even people who /are/ 6 feet tall and 250 pounds tend to exercise reasonable judgement and due caution (as they know they're not invincible) and they avoid areas that may be dangerous and/or keep their wits about them.
Some 90lb weaking who feels invincible merely by carrying a weapon is not going to be keeping their wits about them and is not going to be exercising reasonable judgement or due caution. They would not be exercising the level of caution they would normally exercise if they did not have a weapon and felt vulnerable.
So, when the perp with the gun or knife already drawn enters the equation, they're screwed. Peering at your attacker past the barrel of his firearm is not the time to be reaching for your own weapon - doing so is likely to get you shot.
Knives? There's a reason the cops drill at drawing and firing two shots into the centre of mass within a second and a half - Sgt Dennis Tueller (Salt Lake City Utah Police Dept) wrote an interesting article about it back in 1983 and they named the drill after him. Basically, if the perp has a knife and is within 21' (much further than the range of one of those tasers), you have less than a second and a half to draw and accurately fire the weapon - assuming the perp is "kind" enough to wave it about and make his intentions obvious (rather than get up close, pull it from concealment and ram it into your body at contact range in under half a second - the words "I thought he'd just punched me - and then I realised I was bleeding" spring to mind... you don't always get a warning that they're hostile, let alone armed.)
A weapon is not a panacea and dizzy-bitch housewives selling tasers like they're tupperware (and then keeping them in a locked box with the keys up out of reach of the kids) is not going to do any more than provide other dizzy bitches with an ego wank and lull them into a false sense of security.
Having a weapon on your person in the wrong area of town no more makes you safe or "6 feet tall and 250 pounds" than me carrying a scoped 7mm Magnum rifle up in the bush makes me "The Great White Hunter".
Even if they were to undergo proper training in the use of the weapon, legal ramifications and situational awareness (like through Massad Ayoob's Lethal Force Institute or similar), it's still debatable whether they would be mentally able to use a weapon under stress but at least the LFI or similar would have taught them they're not invincible or "6 feet tall and 250 pounds" and to be cautious and aware of their surroundings - so they'd be less likely to get into danger in the first place.
The USA is seriously fucked up as weapons are sold by PFYs in supermarkets and soccer mums at house parties rather than being sold by proper training centres upon completion of training. Training and practising with them is optional instead of mandatory. And then the untrained morons wander around feeling invincible and that they're just as capable of defending themselves as Josh Hamilton (above), with his weekly training sessions, or a trained police officer.
I'm not opposed to having firearms or tasers for personal defence. By all means have them as there are plenty of illegally-owned weapons out there in the hands of criminals - but FFS learn how to use them properly and learn to be aware of your surroundings so you can either avoid using them or at least have them ready and are competent with them when you do need to use them.
I'm waiting for all the reports on how many perps have robbed someone and scored a nice colour-coordinated taser along with the cash.