Nonsense, a hard reset gives you a clean state to start from. One of the most important aspects of diagnostic troubleshooting is having a starting position with as few potential problematic parameters as possible.
A soft restart, i.e. a normal power cycle restores everything to the same state as it was before switching off. While that is sometimes enough to resolve minor issues it is in no way as useful as having a clean slate to work from.
Hard resets do not affect any permanent information or settings, they simply clean out the many, many cached files and random information held in memory. That saves you the trouble of chasing your tail if a problem is caused by a cached file that would be restored again by a simple power cycle.