Even before your flight, three's already a huge advantage of having to just bring a carry-on with you. You don't have to pay the often expensive fees of check-in luggage with you. More often than not, it's these fees that make your entire airfare ticket expensive. You might be surprised to see that the difference in price are often in the hundreds, at times, even thousands. So just having a carry-on will see you a ton of money—extra cash that you can use for your trip. Also, think of much time you'll save not having to check-in luggage either!
As much as you want to trust your airlines or your city's/country's airport, you can never be too sure if the people handling your check-in luggage are good people. There have been cases—albeit very few ones—where airline and airport staff have stolen valuable items fro people's luggage. Then there's the more often cases of negligence and losing your luggage altogether. What if your laptop or important documents are there and you haven't gotten them yet when you land in your destination? What do you do then? If you kept all your important belongings in your carry-on, however, you can better protect them yourself.
A good pro-tip when traveling is to always pack some clothes in your carry-on. Even if you have check-in luggage, make sure you have a few pieces of clothing in your carry-on. As already mentioned, cases of missing luggage are, unfortunately, all too common for international travel. If you don't put some clothes in your carry on and your luggage disappears, you risk not having a wardrobe for the first few days of your trip. Possibly even for your entire trip. Now, if you only had to bring your carry-on, all your clothes will near you throughout your flight.
In relation to that, when all your clothes are in your carry-on, you can even change your outfit while on the plane. Or if you need to check something on your laptop, packing it inside your carry-on will give you instant access to it. More than just the security that you'll be with your belongings at all times, just having a carry-on allows you to easily access all of your items even whilst on the plane. From necessities such as clothes and medicine to work-related items like important files and your devices, just reach up to your overhead compartment and they'll all be just there!
If you packed all your belongings in your carry-on, of course, it will become heavy. But that's not the point here. At least, if you only have your carry-on, that will be the only heavy thing you'll need to lift, drag, or roll. Now, imagine if you have other pieces of luggage with you. And they'll likely be heavier too. What a chore it will be dragging them all across the airport. Even when you put them on a cart, having to push all of that will really put a strain on you. Before your trip even officially begins, you're already tired!
Finally, after your trip, when you have to re-pack everything again, doing so in just one carry-on bag will be a breeze. It was likely more challenging packing it before your trip because you had to think about and choose what to pack and organize everything so they'll fit perfectly. But now that you're done with the trip, all the clothes have been worn and such, you can simply fit them all in the bag easy peasy. Now, if you had other pieces of luggage with you, you'll have to stress over them as well. not to mention making sure that they're not overweight too!
At times, you can't control what you'll need to bring for a business trip. However, if there will be some travels that you can simply bring just a carry-on bag for all of your belongings, do so! You'll be surprised by how much easier and more beneficial leaving off extra pieces of luggage can be!