A bit boring this, please accept my apologies-
Preparing to land a hang glider, you must get it just right. The big challenge is when you have high residual ground speed- maybe in nil-wind, downwind, or down hill. You must bleed off your speed, then at the correct time induce a controlled stall ('flare')
by swiftly rotating the glider nose-up just as your height is low enough and the speed in the correct zone, and using the sail as a brake. There can be complications in the event of cross-wind, unexpected turbulence or wind shear. One may have to jog along after landing until one can support the glider, and may not be able to keep up with the pace. There's a risk of tripping-up, particularly on rough terrain. Modern hang gliders, e.g. topless gliders have an improved glide angle due to reduced drag, making things even more critical. 'Ground effect', where the wing tip vortices are reduced make the glider travel further on and faster than anticipated.
The consequences of a poorly-timed or inadequate flare can be embarrassing, costly and perhaps even unsafe. The bottom bar digs into the surface, the glider pitches forwards. The pilot may swing forward through the A-frame, possibly impacting the keel with their head. They may graze their knees. The nose of the hang glider may bang into the ground, the uprights on the A-frame may crumple under compression, and the bolted joints may be weakened. The glider may spin horizontally.
A muddy bruised pilot, muddy broken glider and smirking audience. This isn't optimal, although the gloating onlookers are no doubt amused!
Some early career pilots have wheels on the base bar, and these may mitigate some of the issues, aside from the muddy knees, perhaps.
However, if you are teetering on take-off in a stiff breeze, maybe at the edge of a steep ridge or at the top of a ramp, in the event that a gust comes through and lifts a wing, you will really want to place the base bar down and take a pause. It's then when you will find the wheels unhelpful. This may be why many people eschew their use.
My suggestion is wheels which can be locked prior to take-off, so you can plonk the glider down on them to stabilise your stance. After take-off In flight, at your convenience, you can throw a lever to unlock each wheel in order to be ready for landing.