Some places require them. We have a sturdy aluminum expanding support.
Most of the time it is too tall to use from our coach.
The plastic things are very aggravating with a bad back. The sewer hose gets heavy when emptying and flushing. four inch pipe full of water etc. If they still make the aluminum ones, I want a shorter or less tall one.
If just over nighting, I may not connect but usually do so it won't take as long to prep to leave in the am. Always travel with emptied gray and black tanks.
In places like La, Tx I won't connect because until I dump because of ants.