Encaustic is one of the most versatile mediums I've ever used. It can be poured, carved, scraped, layered, collaged, dipped, cast, sculpted, textured, combined with oil and pastel, and more. And, it cools immediately, perfect for impatient painters like me, so there's minimal cooling/drying time. Plus, it can always be reworked.
As for melting, which many clients ask me about, the wax/resin/pigment liquifies at around 200 degrees, so the concern of it melting in your living room on a hot day is unlikely. It's most suitable at room temperature (75 to 80 degrees). And any painting, whether oil, acrylic, watercolor, etc., is also best in a cool, shaded environment. Temperature is usually only an issue during transport, which I will address later. Encaustic also doesn't require varnish or protection by the glass because wax serves as its own protectant. Wax resists moisture far more than resin varnish or oil. Also, buffing the finished surface of an encaustic painting gives it a high luster similar to resin varnish.
As for concern about a finished piece yellowing or darkening, encaustic won't do this either. The wax, however, is photoreactive, so unpigmented encaustic medium kept in storage may darken slightly. But when re-exposed to light it soon returns to it's original, vibrant color, especially after a good buffing with a soft white cloth. The most care must be taken during transport. Edges are susceptible to scrapes or chipping. In this case, the artist can repair damaged areas with a torch or heat gun. It's best to ship encaustics in a controlled temperature of about 85 degrees. Too hot and it may become sticky; too cold (below freezing) and it may shatter. But when properly packaged and handled, an encaustic painting can arrive safely to its destination, where it will last indefinitely, impervious to moisture damage and rot. Many ancient Greco-Roman encaustics, painted more than a thousand years ago, remain vibrant to this day.