One of the problems with any Search engine, is that you need to have a reasonable idea of the answer. You cannot, for example, put in a picture of a plant and ask what it is, which you can do on here and other garden sites. Phrasing the search question is an art in itself to avoid the tedium of false leads. There is also the problem of targetted advertising from any Search you make. Useful to have Do Not Track Plus and Adblocker on your Browser.
It can be useful. Someone on here posted a question as to the identity of a plant giving half the name. I found it on the Web from that scrap, but it took a little searching and some knowledge of plant names to do it.
But I will tell you one thing which really annoys me, is the practice of answering a question by using a Search engine and posting the link to the answer found, instead of writing the answer for the questioner. I never follow links like that.