Mercenaries are valuable in 21st century conflicts. This is because mercenaries increase the military defense operations. If there is a way for our military to be stronger and more prepared when it comes to a possible attack, then I would say that using them would be the best option to use.
Yes, mercenaries are valuable in 21st century because they increase military capabilities. Without mercenaries, most countries would be able to be strong enough to protect their nation's interests. However, if a country is economically sound and can build up their military with mercenaries, there is no reason they should not be able to.