Ring doorbells compatible with existing chime

Hello, I was looking into Ring doorbells and little bit puzzled which models support existing doorbell chimes. I have an 20 yrs old German doorbell system powered by 13V AC (measured by multimeter) transformer located in an unknown location. I don't want any additional chimes so I want to hardwire the Ring doorbell to the existing doorbell system using the existing transformer and chime. DYI installation is a must. I was looking at base model Ring Doorbell Wired but in the installation instructions it says that one has to bypass the existing chime, logic of this escapes me? Please advise.