I had a weird game last night on Junkertown defense where the other tank kept insisting on playing cart.

Context:

2nd point Junkertown, I was playing Orissa on highground around the balcony/top stairs area. The cart was pushed past the corner, near the mega in hell. We had already won two team fights from the highground, but in the 2nd team fight, they managed to push it past the bridge to the previously mentioned area. Our Sigma kept wanting to play cart but I felt it was better to fight from highground (as did our dps).

Now the beef came when the opponents pushed past the bridge area, and I was essentially on their right (up the stairs) and Sigma was on their left (on cart). We won that fight and that round but not before Sigma kept screaming to play cart and essentially saying "noob team".

My question would be when should you drop to fight cart? I know that highground is much better to fight from and it doesn't matter too much how far the cart has been pushed as long it is before the endpoint. But is there a cue that tells you it is time to give up highground and play point? I know my choice in tank wasn't that good for 2nd point but I was 80% to supercharger when we lost 1st.

Edit: thanks for all the comments guys! Really learnt a lot from the discussion. For those that are curious, we were Orissa, Sig, Genji, Soldier, Ana, Zen playing into a Rein, Dva, Reaper, Soldier (IIRC), Moira, Ana (IIRC). Which was why I filled in the tank role as Orissa, even though I don't play her a ton.