Well, that's nice that you've never had problems. But issues I've seen over the years, range from not having certain functions working after the flash (generally needed specific firmware upgrades prior to the flash), not having the device recognized by the PC without additional steps, needing specific custom recoveries, bootloops, being stuck on splash screen, needing extra steps to unlock the bootloader (e.g. Xiaomi), not being able to easily downgrade Android version (sometimes needed as a first step prior to installing alternate OS's like Ubunu Touch), even soft bricking. Plus, in learning how to flash custom ROM's in the first place, guess who provided me with the info on how to do it.