Whiskey stones solve a problem many drinkers do not actually have. They promise cold whiskey without dilution, but they cannot absorb heat like melting ice can. The drink may cool slightly, then stall. Ice, by contrast, chills through both temperature and phase change. As it melts, it also adds water, which can open aroma and soften the edge of a strong pour.
That does not mean every whiskey needs ice. If you are tasting a bottle carefully, start neat. Add a few drops of water if the alcohol feels tight. Use one large cube if you want the drink colder, slower, and more relaxed. Use regular cubes if you prefer more dilution. Skip stones unless you simply enjoy the object and accept that the cooling effect is modest.
For cocktails, choose ice almost every time. An old fashioned, highball, or whiskey sour is built around chilling and dilution. Removing water from the equation can make the drink hotter, sweeter, or less integrated. The home bar lesson is simple: control dilution instead of fearing it.
If you keep whiskey stones, store them cleanly and use them only in spirits you already enjoy near room temperature. Do not expect them to rescue a warm drink, and do not put them in delicate glassware where they can chip the rim.
Further reading: Good Housekeeping on ice clarity and dilution and background on cocktail chilling in shaken, not stirred.
