It would likely not be very useful even ignoring the speed aspect.
A lot of work goes into making a search engine understand how a term relates to a website, and to rank the results accordingly.
You might get lucky and search for something that's in the goldie locks zone between underspecified and overspecified, and actually get good results, but in most cases you'd either get nothing or just noise.
Unix grep works well because you're typically grepping in hundreds or thousands of documents, not hundreds of millions or billions.
A lot of work goes into making a search engine understand how a term relates to a website, and to rank the results accordingly.
You might get lucky and search for something that's in the goldie locks zone between underspecified and overspecified, and actually get good results, but in most cases you'd either get nothing or just noise.
Unix grep works well because you're typically grepping in hundreds or thousands of documents, not hundreds of millions or billions.