Yes, the weight of the tent, helped by a good gale wind and some sheet tension will overload the mast top and create a permanent bend. Remember that the Wayfarer has a 3/4 rig (or is that a 5/8 rig?). The mast top is not supported by stays or shrouds. Also the mast is made to bend easy to flatten the sail. Basically it is a racing mast. Such a light mast is easily overloaded without proper support.
While setting the tent it is virtually impossible to adjust the topping lift, the mainsheet and kicker such that the boom is in the exact position the tent requires. With a crutch it is a no brainer.
I use a topping lift only while cruising and to avoid fouling the helm and engine. As soon as circumstances allow I replace the topping lift by the crutch. While the boom is on the topping lift I take care not to put any tension on the mainsheet and kicker. With the mainsheet loose and no kicker, the boom does swing about a little. But rather that then damaging the mast. Basically I need the topping lift only if I need to switch from sailing to motoring in a hurry. In all other cases I try to avoid using it.
Two pieces of wood and some paint seem a small price to pay compared to a new mast. And the crutch stores easy once folded.
A crutch is also helpfull in lowering the mast while shooting bridges or while removing the mast if you have a compass on it that, due to a stubborn builder, will hit the CB horn when the mast is lowered.
By the way, my topping lift is at the mast top for it is also my spare halyard. Some use a topping lift at the hounds where the mast is supported by the shrouds and forestay. Perhaps you could do without a crutch if your topping lift is at the hounds, I am not sure. Still, it would be easier to use a crutch with a tent. Just think of the forces on the rig when the tent is set and the topping lift taut while on anchor in a gale wind and 2 feet waves…….. I wouldn’t sleep well, but I would with a boom crutch.