You’re in the middle of a video conference, everyone is waiting, but your microphone isn’t working? Or you can be heard, but all the other participants remain mute? Welcome to the club of Windows ...
Whether or not adding a sound card makes sense really depends on how you're regularly using your PC.
If these were the early 2000s. We would have said that having a sound card is a flex. With good reason, too. You'd slap one into your PC, crank up a media player, and pretend you were mastering audio.