Earlier quoted context omitted.
It's nice, but unfortunately listed on nearly every tour guide of Chile, so these days it's flooded with tourists most of the time. You'll have a much better time seeing other places slightly off the beaten track.
During the summer months yeah, but I've been there last year during the end season and, although there are still lots of tourists, it's not overwhelming and some of the hikes were pretty chill. Going straight to the Torres themselves will usually be crowded (depending on the time of the day). But some of the other hikes less so. I've done the W Circuit (a multi-day trek) and during some days I barely saw another hike…
I visited Torres de Paine and it was refreshingly different from national parks in the US. On the upside, you can get water and basic snacks at the refugios which reduce the load you have to carry, and makes for an overall safer experience than unsupported wilderness backpacking but still with minimal impact on nature. On the other hand I did not like that they close a lot of viewpoints long before sunset.