First of all we will have to have an introduction on flash memory. Flash memory has a high buffer and it is non-volatile.
When non-volatile it means that, it does not need electric supply to store contents in it. You can think of it like the pen drive that we all use.
Now hybrid drive is one which makes use of a highly buffered flash memory.
Why are these drives faster?
Normal hard disks which we use consist of platters which make use of sectors to locate data. The sectors are located by rotating the platters. The rotating and locating slows down the normal hard disks.
In case of flash drives, the absence of platters helps us locate the data easily and hence flash drives are faster. Due to the high buffered flash memory used in hybrid drives these drives are faster.
Hybrid drives are currently costlier and it will take a while until it is highly commercialized.
Some of the improvements that can be made using these hybrid drives are the decrease in the boot time of computers, high speed data transfer, high memory optimization etc.
Also the spinning of the platters in case of a hard disk increases the power consumption and heat generation. This could be very much useful incase of increasing the working time of laptops as these would use only very limited power.
The only problem with this drive is that it increases the cost. It is faster when cached data is used, and may be slower in case of un-cached data. Files which are lost are difficult to recover when using hybrid drives.