And how would you suggest that it is made more attractive ?
I have run schemes for employers of between 100 and 50k employees and have found it to be the least administratively cumbersome and easiest to explain benefit scheme there is!
For the employee it is attractive as they can save up to 50% of the cost (as VAT can often be reclaimed) as well as being fitter - they also appreciate the tax free cyclists breakfasts that you can provide for them every now and again.
For the employer the NI savings far outweigh the time spent on it (I once worked out that each application took me 3 minutes to check approve and process) and it really does promote your companies green agenda.
Rather than just looking for the obvious think of the unusual - if people come to work by train they are allowed a bike under the scheme to get to the station (and another to ride from the station to the office as long as the combined value of both is less than £1000). Speak to your local council about cycling routes, invest some of your NI savings in cycling training or cycling proficiency tests, promote safety equipment as well as just bikes, organise events / competitions / incentives for those that do cycle.
Given that schemes are free to set up and promote and take no time at all to administer surely just one person taking advantage is a good thing ?