Not to hijack the thread or anything but I've never considered buying a sound card before, I figured with digital signals the only important part was the end point, so like an expensive pair of headphones was all you need for decent audio.
For a USB headset, that's largely true, as the headset contains its own hardware for converting a digital signal to analog, so additional sound hardware is not needed, though you are dependent on whatever hardware they managed to cram inside the headset. And in the case of a wireless headset, the digital signal may be compressed prior to transmission, potentially reducing its quality in the process.
For a headset with 3.5mm jacks though, the signal is getting converted by the computer's sound hardware, whether that is onboard audio on the motherboard, or a dedicated card.
Also, it used to be that offloading 3D sound processing tasks to dedicated hardware on the card could reduce processing load on the CPU, though that was more relevant back when CPUs were slower and had only one or two cores to work with. I believe most games do their sound processing in software these days.
I have a Creative card in my current system, but it's an older model, and has recently started experiencing "crackling" at times that requires a reboot to correct. I intend to build a new system soon, and will probably try going without a sound card, seeing as onboard audio has seemingly improved in recent years.
As for whether it's "worth getting a sound card for gaming", I would say that at this point, it's probably only worth considering if you don't have something better to spend that money on, or have some specific need for one. For someone with high-end components like an i7-8700K and an RTX 2080, along with higher-end audio equipment, spending $150 on a higher-end sound card like a SoundBlaster AE-5 might be considered reasonable to get a little more out of the system. For a more mid-range setup though, you would probably be far better off putting that money toward other hardware, like a better graphics card, or a better monitor or something. In the mid-range, putting an extra $150 toward a graphics card is likely to get you substantially higher frame rates, whereas putting that toward a sound card might get you slightly better audio quality. So I wouldn't really say it's like the difference between onboard and dedicated graphics, since onboard graphics tend to barely be able to run modern games at playable frame rates at the lowest settings, whereas onboard audio tends to come relatively close to what the dedicated cards are doing.