The simple answer is yes, but that doesn't mean to go wildly swinging your coil to gain depth or you will miss far more targets than you will gain. The filtering systems of metal detectors are looking for a change in the ground matrix, (mineralization/metals) and the faster the change, the more reliable is the target ID. Keep in mind that the detector first has to locate a target, and on deep targets, any detector needs time to analyze the data it is receiving. That is why swinging too fast will not give the detector time to analyze available information to determine if it has located a good target among the bad, especially when a target is deep. If you are clad hunting and only want the top 4 inches of ground, yes, swing as fast as you want, but if you are looking for the deep ones, slow way down.
Once a deep target is located, you can then use the fast swing to your advantage to help you determine if a target is something you might want to dig. We use what is called the wiggle over a suspected target. Quickly wiggle the coil over just the target in question and the detector has only the data from a very small area to analyze. If your signal breaks up or sounds worse with the wiggle, you likely have something you do not want to spend the time digging. If the target sounds better or the same with the fast wiggle, I dig.
Some detectors are what is known as a "fast swing" detector because of, primarily, the processor speed and the amount of filtering. The more filtering, the slower the swing. White's is a fast swing detector. Minelab on the other hand works best at an ultra slow speed, yet still benefits from the "wiggle".
I hope this helps.