OBS will not directly cause hardware failure in any way.
Realtime video encoding is a VERY demanding process though, and will run your system beyond 'normal use' levels. Still within spec, it's just that video encoding will stress any machine. Slimline systems like laptops tend to have very poor thermal envelopes, which can cause thermal throttling quickly on cooling solutions not meant to handle full system output, especially under strenuous conditions.
So no, OBS won't break it. But OBS (or any realtime video encoding program) might reveal already-existing flaws that are present in a system, that mild or 'email machine only' use may never stress the system enough to activate.
For example, if a dab of cheap glue is all that's holding a video ribbon connector cable in place, and running the CPU at maximum for an hour can't be curtailed enough by the cooling fan/radiators, and the entire system starts to heatsoak, causing the glue to soften, and the ribbon cable to fall out of its seat. OBS wouldn't cause that, the heat of the system did. Even if OBS might be the reason the CPU was running at full-rate for an extended period. It'd be a design flaw in the hardware that ANYTHING causing high extended CPU use would trigger.
