When our two children were younger, they didn’t like the boom coming down when the sail was lowered. I fitted a topping lift to keep the boom up and out of the way. It was also easier to tidy the sail by rolling it round the boom with the aft end supported by the topping lift. If you’re into rowing, it makes that easier too, but I prefer paddles to oars.
Disadvantages were the occasional difficulty in getting the mainsail to the top of the mast (the topping lift shackle could foul the top of the sail)
On the whole, with young children, it did the job, but a year or so ago, they voted to have it removed.