Cut crystal glasses aren’t to my taste, but the risk from drinking out of lead crystal glasses is nigh on zero. The risk from storing drinks in lead crystal decanters is minimal. The lead content is an integral part of the glass structure and can’t come out unless the glass is dissolved.
Bear in mind that “proper” lead crystal glass is about 40% lead oxide. “Modern” lead crystal is only about 24% lead oxide and is significantly less soluble than the 40% lead [oxide] crystal. I used to make glass with 80% lead oxide content (for use in camera lenses and nuclear shielding) and it was perfectly stable.
Lead oxide increases both the refractive index and dispersion (separation of colour) of the glass, lending it brilliance and colour, as well as making it easier to work. Modern, lead free alternatives can get close, but they lack the clarity and freedom from colour cast that real lead crystal possesses.
Much modern “crystal” glassware is cheap, moulded stuff. Ergo: Pick something you like and buy it.