Earlier in the year, it was reported that there was a flaw in the Nintendo Switch hardware which made bypassing the system protections fairly easy. These types of issues exist fairly often in modern hardware, as firmware developers reply on the ability to patch too heavily. The issue here is that the flaw was in the Tegra X1 chip provided by NVIDIA, meaning that software alone could not guarentee success in preventing owners from hacking the system.
According to Twitter user @SciresM, however, new batches of Switch units have been pre-patched for one of the known exploits. They are, however, also shipping with version 4.1.0 of the system firmware, which means that the systems are not entirely devoid of known vulnerabilities. In this case, Deja Vu, which is an exploit that was patched in firmware version 5.0. The discrepancy suggests that the chips were patched in the factory before the Fusée Gelée exploit was made public, but before Deja Vu was known.
This is bad news for people who are interested in making the Switch do things that it was never intended to do. Some of these things are innocuous, such as making it run Windows 10. Others, however, are not nearly as above board, such as running system emulators. While emulators are not themselves illegal, they do promote the use of unlicensed software which is illegal. While Nintendo does not particularly care about the first scenario, the second can cause problems.
In addition to running unlicensed software, a hacked Switch could potentially also make it possible for players to cheat in a game. For example, with a game like Splatoon 2, a popular multiplayer game on the platform, a hacked console could automate certain tasks making it easier to win a game. If you are the owner of that particular Switch, that might provide a little fun, it certainly ruins the experience for the other people in the match.
If you want to use the Switch for something that it is not intended for, you might want to get one now.