So called ’passive’ bi-amping, feeding both LF an HF full range and still maintaining the stock passive crossovers is simply a waste of money. It maintains all the drawbacks, eg cost and complexity, while providing none of the benefits of actual bi-amping.
There are pros and cons with every option. That statement immediately dismisses the separation advantages of using a separate amp on each channel that occurs with a vertical bi-amp setup or monoblocks... with active or passive crossovers. It also dismisses some exceptional well designed passive crossovers that bring a performance level that can rival or surpass some active crossovers. Neither active or passive crossovers are created equal...there are excellent and poor examples of each. Doing an active crossover well still requires some user input to get it right, and there’s certainly no guarantee it’ll happen. With a good passive crossover you know exactly what you have.
I’ve been running my tube amps full range as monoblocks for a while. I just recently added a used integrated amp for $50 to drive the woofers (horizontal bi-amping) Not expensive at all, and still offers an audible benefit and a ton of flexibility without active crossovers. When I was running them in a vertical bi-amp configuration (still with the passive crossovers) the soundstage was incredible.
The point is you can start very simply even with passive crossovers and still get some benefit from bi-amping, and have the option of adding active crossovers down the road if and where you choose, or use a combination of passive and active crossovers. Bi-amping offers tons of options and flexibility, and can let you get pretty creative.