Let's first look at the purpose of each.
CHALK is intended to create a no-slip grip between your skin and whatever you're holding onto. In the case of powerlifting that would be the barbell. For other weight training it may be dumbbells or kettlebells. In rock climbing it'd be the wall, and the list goes on.
GLOVES are intended to prevent the formation of calluses on your hands.
The two do not serve the same purpose.
In fact, gloves actually ADD an extra layer of slippage, which is the opposite goal of chalk.
And chalk ENCOURAGES the formation of calluses, which is the opposite goal of gloves.
To equate the two or ask "which is better, chalk or gloves?" is somewhat silly...
If your goal is to add friction and prevent slippage during your lifts (or other sport) then chalk is the way to go. Gloves would just get in the way. But, if your goal is to prevent calluses from roughing up your hands then gloves are your solution. I do have something to say about that though...
If you're a serious lifter or athlete you should not be concerned about calluses. The formation of callused skin on the hands is your body's way of adapting to weight training (or other sport), and I would argue that it's a healthy process. This adaptation is natural and useful, and wearing gloves inhibits it from occurring fully or at all.
Additionally, as your calluses mature they will actually help your hands feel less sore from training. This is evidenced simply by the soreness and discomfort of the hands after taking an extended period off and then returning to your regular training sessions. The time off allows the calluses to recede and soften, which prevents them from fully serving their protective purpose until they've had a chance to build back up again.
'But couldn't I just wear gloves all the time and not have to worry about soreness?'
...Sure. You could. But then become dependent on the gloves and never form calluses.
And, this isn't my only qualm with gloves...
- They get sweaty and stinky.
- You can't wear chalk with gloves, or rather, wearing chalk with gloves is useless and unhelpful.
- They get worn down and have to be replaced fairly often.
- It's just another thing to remember to pack in your gym bag, which can be really annoying if you're already thinking about a your music and headphones, recording journal, belt, shoes, pre/intra/post workout drinks or snacks, etc.
- Honestly? They look pretty silly. I've always thought so... even when I used to wear them!
- Lastly, if you're a competitive athlete of any type and gloves aren't allowed in competition then it's really counterproductive to train with them.
Chalk, on the other hand (specifically liquid chalk, which is what I'm going to recommend) has some pretty big benefits:
- Easily portable
- No mess or residue (again, liquid)
- No odor (liquid)
- Enhances performance by improving grip
- Encourages formation of calluses to protect the hands and relieve soreness
So, when asking which you'd be better off using you have to think about what your goal is. Do you want to prevent your calluses from forming? (Aka: do you want to try to keep nice, soft hands?) Gloves. Or do you want to enhance your performance? Chalk.
Let's lastly talk about a few specific usages of chalk in the weight room:
This is, in my opinion, the most apt use of chalk as grip is a major limiting factor of deadlifts. Having chalk could really mean the difference in succeeding or failing a really tough attempt.
2. PULL UPS/CHIN UPS
Again, grip can be a limiting factor of these exercises, so improving grip may allow you to hang onto the bar just a bit longer or with more ease from the start.
3. BACK SQUATS
If you're wearing a tank top and you're skin is sweaty the grip between the bar and your back may suffer. Chalk, again, can eliminate this issue.
The same is true in a t-shirt. Often times the material of the shirt is slick enough to reduce grip, and chalk can come in handy.
4. OVERHEAD PRESS
If you use a thumbless grip during your OHPs chalk on the palm can help hold the bar in place for the heavier reps.
5. PROLONGED-CARRY EXERCISES
This grouping would include things like farmers walks, yoke walks, and static holds; something where you're just holding onto the weight for a time or a distance. You can imagine that the longer you utilize your grip the harder it becomes, and chalk can be really beneficial for keeping a strong grip during exercises of this nature.
These are certainly not the only ways to use chalk for weight training.
Barbell rows, dumbbell lifts, and kettlebell movements could all be improved with chalk.
Really anything where there is the possibility of the weight (including your body weight, as is the case with pull ups/chin ups, rock climbing, or yoga) slipping out of your hands could make good use of chalk.