Colonizing Venus with floating cities raises the question, Why build the cities floating in the atmosphere?
Because the atmosphere has raw materials for construction and building breathable atmosphere, and because the planet provides gravity that you’d otherwise need a large rotating habitat or tether-and-counterweight system to achieve, and a human-friendly temperature range that removes the need for complex thermal control systems. Venus is effectively the only other source of nitrogen in the inner system aside from Earth itself, and although Venus is very dry, the atmosphere does contain water, and sulfuric acid which can be converted into water or itself used in industrial processes. And the atmosphere is primarily CO2, which can provide carbon for polymers.
Once bootstrapped, small supplemental shipments of minerals and machinery would allow enormous expansion, the atmosphere itself providing building material and lifting gas. The Venusian habitats could provide atmospheric gases and polymer building materials to the inner system. In reality, it is probably one of the easiest places to establish large Earthlike habitats. The plentiful sunlight, ease of constructing large habitats under Earthlike gravity, and constant supply of CO2, nitrogen, and water from the atmosphere could make it an agricultural center for supplying the inner system as well…not only with food, but also chemicals and materials derived from plants. And yes, the rocket fuel for getting things into orbit could also be synthesized from the atmosphere, and the thick atmosphere makes Venus itself one of the easiest planets to land on (even if you never actually touch land).
Converting CO2 to building material sounds like science fiction, but it is a fact that plants do it all around us.
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The advantages of Venus are Earthlike gravity for small, non-rotating habitats, an environment with Earthlike temperatures and pressures and protection from radiation and micrometeorites reducing structural mass and the consequences of a breach (seal the compromised area off, then put on hazmat suits and patch the breach), plentiful availability of nitrogen (which Mars or orbital habitats would need a constant supply of), and sunlight for crops without concentrator mirrors.