During marketing campaigns of the 70's & 80's, manufacturers started to widely call just about all of their craft larger than 30ft lwl Yachts, and that's skewed what the general perception of what a 'Yacht' was previously. At the same time they started using the terms "Super Yacht", and "Mega Yacht" to distinguish those extravagant craft which used to just be called simply 'Yacht'. Like the OP, I prefer to use Sailboat & Powerboat, as it conveys a more concise idea of the craft being spoken of. Take the following potential conversation for instance:
"We'll be meeting @ my Yacht down on pier 32 @ noon." A party who has never seen the vessel would arrive at the dock and have no way to narrow down all the craft since there are 30 boats of all types moored there. If instead one offered "We'll be meeting @ my Sailboat down on pier 32 @ noon"; a party who's never seen the vessel would be able to immediately eliminate a wide variety of craft and simply look at the 12 or so sail boats, thus more quickly spotting his intended destination. Not that it's all that important, but I personally prefer the use of language as an efficient tool of communication - therefore I'll always preference use of the most descriptive term available, which allows for brevity, that conveys the message I intend. Use of sailboat vs yacht simply eliminates a number of questions - thus is a more efficient descriptor for communication. imo
But alas, don't expect manufacturers to stop calling most of their craft Yachts. They well understand that 'Yacht' is a term associated with the more well to do, thus can be used to their benefit in the sales process.