Why wouldn't it be? It's faster than the tram; a bike is cheap and cycling is free; its way easier to park than a car; its healthy; there are cycle paths everywhere (inside and between cities); and everyone else does it, so you usually have company.
While cycling is obviously much, much cheaper than a car, I'd argue its a myth to say it's 'free'. Start commuting a _reasonable_ distance regularly by bike and you are going to incur running costs, as well as often not insignificant investment in essential accessories you might need depending on where you live - clothing, panniers, lights, helmets, locks... There's a fair amount of things on a bike that, like many o…
Mine came with a lock and lights. Tires last 10 years and aren't that expensive. Pumping tires has to happen a few times a year, come on. Never replaced a chain before the rest of the bike was due for replacement anyway. Never heard of anyone replacing cassettes. Lubricant is not expensive for how much it's needed (a euro a year maybe). New brake pads aren't expensive and they last years, disks last decades no idea how expensive they are (my bike from high school still doesn't need to have them replaced). Never used a pannier. Never wore a helmet that I can remember (I've had this discussion before here... I don't know anyone who wore one, nor anyone who sustained serious injury due to not wearing one). And special clothing, huh? What's wrong with the clothes you're wearing?
You're greatly exaggerating. The only expensive part is buying a good one when it's new.