Probably not an issue for a desktop since no one would want to use it under heavy swap all the time, but for a server no one pays much attention to... maybe.
SWAP on SSD or NVMe is still miles better than HDD, you can notice the difference when the swap is being used.
Turns out that the app grew huge over time and the machine would swap like crazy and would eventually slow to a crawl. The machine was already maxed out on RAM, so we added a service to restart the app twice a week. Finance said it took hours off their month-end work, they thought the app was just slow.
You can also monitor swapping activity in iotop. If need be, this can also be written on third party tools, the interfaces are exposed by the kernel after all.
Oh and you can use the modern PSI monitoring of the kernel to measure how much pressure a subsystem is experiencing, so you can restart services way before you'd even notice the swapping on other tools.
At least in my experience, it's pretty hard to actually gauge memory use, but swap use makes a reasonable gauge most of the time. There are certainly many use cases where the swap use ends up not being a useful gauge though.