A single Electron app is usually not a problem. The problem is that the average user has a pile of Chrome tabs open in addition to a handful of Electron apps on top of increasingly bloated commercial OSes, which all compound to consume a large percentage of available resources.

This is particularly pertinent on bulk-purchased corporate and education machines which are loaded down with mandated spyware and antivirus garbage and often ship with CPUs that lag many years behind, and in the case of laptops might even have dog slow eMMC storage which makes the inevitable virtual memory paging miserable.