>cant see that they are really needed
As with much safety equipment, they aren't needed 'til they're needed - I take it you don't ride without helmet and/or you do ride in T-shirt, shorts and flip-flops?
The bead clamps will stop the tyre coming off the rim if it deflates suddenly. I've had punctures with and without the clamps, while either is a good natural laxative, with a bead clamp is much less so.
Tyres aren't any more difficult to remove from or fit on a rim with bead clamps. Decades ago, a north London tyre fitter showed me how, I've done 'em the same way ever since. The tricks are: fit the clamp between the rim and the tape, undo the nut only as far as the end of the clamp stud; as either you fit the tyre bead near the clamp or the machine gets near it, push on the end of the stud, the nut'll stop the clamp falling into the tyre; when you stop pressing on the stud, the tape'll push the clamp/stud back out.
Tyre fitting, fit the tyre as normal, seat it as normal; when you're happy, tighten the clamp securing nuts.
This is difficult?