I am somewhat familiar with that battery charger as I once used a Truecharge 40+ for years. Yes, the converter could be eliminated. A two or three stage battery charger will charge battery banks up much faster than older stepdown transformer types. Some converters can simple be disabled by disconnected their AC input and nothing be done with the DC side. The battery charger can be installed in any location near the old converter or the batteries and accessible if it has switches for battery types and temperatures to include battery equalization.
The charger should be secured with fasteners in a suitable location. AC power can be run from the same circuit breaker that supplied the old converter or another suitable source. The DC output can be connected directly to the batteries as that is how the charger senses the charge rate for the batteries being charged. My Truechare 40+ had a switch to select a fixed 13.2V output so it could be used as a converter or a two or three stage battery charger, however it only did the function selected.
Ideally if possible, I would try to retain the old converter to power the coach, while the battery charger charges the batteries. That would be easy to do if the converter has DC output for the coach and DC output for the batteries, automatically disconnecting the batteries from the coach DC distribution system when plugged into shore power. Just disconnect the converter battery output in that case and be done. If the converter only has a single output, a separate 120V high current relay could be used to disconnect the coach batteries from the DC distribution system. The main reason I like retaining the old converter is due its lower DC output voltage around 13.2V. A battery charger can approach 14.8 DC volt output. That is great for charging batteries, but it is not so great for solid-state control boards for refrigerators, furnaces, or any electronic device in the coach that are 12V powered.
That charger would make a great project for a coach with an older inefficient converter allowing the old converter to power the 12V devices on shore power and 100-percent of the battery charger output to go to the batteries. A 45-amp converter with a 40-amp battery charger might approach similar performance to a newer style 80-amp converter/charge. It obviously will take some electrical knowledge and all wiring should be installed following NEC codes for health and safety.