or maybe its a method of commuting for workers?
Not if you need another method of commuting to carry your method of commuting, at the cost of passenger space, it isn't.
Cycling is an activity, that's all it is and that's all it will ever be. Yes, you can perform that activity on your way to work, if you live close enough, just like you could skate board or roller skate to work, or even simply jog to work, but as a method of commuting, this whole "cycling to work via train" as currently performed by many individuals is effectively in the same class as horse riding or kayaking to work via train would be. You wouldn't expect transportation methods geared towards genuine commuter to make adjustments and facilitate carrying horses or kayaks, why are you surprised that bicycles do not belong there?
Cycling as a form of commuting is not only recreational, but also very practical vs the London underground/ walking.
Only for the performer of the activity. Pedestrians hate it, drivers hate it and apparently commuters on trains hate it too, but it's not like it ever stopped anyone from cycling...