hand held flares for signalling in any forested area is useless unless you use them to start a forest fire. The tree cover would block most if not all of the "signal".

Hand held flares for self-defense is no better or worse than a flaming torch. Difference is if you pull a flaming branch from your campfire and wave it around you still have the campfire as well. The hand-held torch will go out before the patience of the furry aggressor. Also there are serious deployment issues with flares for defense. A bear will be charging at something close to 30 mph from a distance of less than 100 yards. This gives you ~5 seconds to deploy. With a revolver you might get two rounds out. With a hand-held flare you will still be trying to get the cap off when the bear munches down on your cranium.

I think that the true risk from critters is much less than the risk from the maniac in the car next to you during your morning commute. We go through our daily lives taking and ignoring greater risks all the time. This isn't an argument for lack or preparation but rather for reasoned preparations. If something is impossible to prepare for adequately (nuclear blast, meteor strike, 747 flying into our office) we will deny it or accept the risk, if something is too low probability to be worth the cost of preparations (lightning strike, meteor strike, flood in the mountains, Iceberg in the tropics) we will accept the risk, if something has low - no serious consequence (button falls off, finger scraped pulling a circuit board, drivers arm sunburn) we will not bother preparing for it. We must evaluate each situation that worries us and really do the research on the statistical probability and severity of consequences and effectiveness of mitigating preparations to determine if it is worth worrying about.

In the case of defending yourself while in the wilderness the only effective defense is a firearm and proper training. The training should cover the means of avoiding conflict as well as handling conflict. The simple expedient of tying a cow-bell to the top of you hiking staff is sufficient to ward off almost all wild-life attacks. You might still be stalked by a carnivore like a large cat but omnivores like bears won't be surprised by your appearance and therefore won't be seen by you or threatened by you and so won't attack. If you are in circumstances where humans are your problem then you either must evade and escape or kill and nothing beats a gun for those options.

BTW deploying a firearm while an attacker (bear or human) is charging you is much different than target shooting at the range. This is a skill that must be practiced while under stress and fear.