Waste heat is not free to the degree that you're not cooling your cold side as efficiently. If "sending heat to homes" has the same thermal resistance as "just dissipate it", then sure.
However, I find it elegant that heat is directly used to heat homes, rather than turning it into low-entropy electricity just to turn it to heat again (which is inelegant, even with heat pumps).
A natural gas furnace is up to 98% efficient. A natural gas turbine is 40-60% efficient; a modern heat pump can have a COP of 3 or even 4, for 150-200% equivalent efficiency (ballpark).
However, I find it elegant that heat is directly used to heat homes, rather than turning it into low-entropy electricity just to turn it to heat again (which is inelegant, even with heat pumps).