Hi,
Product Manager for Datasheets.com from SiliconExpert here.
Good to hear your perspective.
Datasheets.com has direct relationships with hundreds of electronic manufacturers and dozens of distributors. As such, the likelihood of finding a part number on datasheets.com is greater than any single distributor/manufacturer website by itself. I would encourage you to try a search. Let us know how it goes.
Also, Google searches for part numbers can at times provide non-electronic industry related results. Simple example: search for "DMV" on Google and you will most likely receive results for the Department of Motor Vehicles. Search for "DMV" on datasheets.com and you'll see results for Diode families from electronic manufacturers.
The difference really is between horizontal vs vertical search engines.
We understand and do agree with the usual route users use. One of the many compelling propositions to use datasheets.com is to search on parametric data and compare parts. For example, if your current part is obsolete and not available, as a design engineer you can search for various parameters and find a replacement part.
Also, our engineering team normalizes part data which makes it easy to compare various parts with similar attributes.