and by not having to install rails they’re a lot cheaper too.

The main reason I dislike buses compared to rail is that the very things the engineers and operators consider to be advantages -- the less need for permanently-installed infrastructure and therefore greater flexibility for changing routes -- I consider to be disadvantages because it means the routes can't be relied upon to stay put. With rail, once that line is in, it's in, and it's safe for the people along it to plan their lifestyles accordingly. Transit-oriented development, for example, isn't likely to happen along a bus route the way it is along a rail line. Residents are a lot more hesitant to go car-free when the risk exists that the bus route they rely on could be cancelled or changed one day. The visible infrastructure of a rail line signals long-term investment in the community (thus making it more attractive for development) in a way that mere bus stops do not.

I realize that you're talking about trolley-buses, not regular ones, so the existence of the catenary wires might help mitigate these issues. Still, I don't think it would be a strong enough signal to achieve the desired effect (especially since the wires are the ugly part of an electrified transit system, and the community getting only the ugly part is kind of a signal of its own, LOL).