It seems to be steeper than Bitcoin. Why is this?
There's no definitive answer to this (I've asked the devs in the past and they' don't know either) because the original guy that announced Monero, was thankful_for_today and he's no longer around. However, it does seem that the issuance schedule and Monero's does seem to match up so that both reach a total of 21 million coins in the future. This MAY be coincidence, but it's likely because the creator wanted to create a fairly closely matching issuance that was on par with Bitcoin's.
So to reach the same level of disbursement to miners, and since there is a tail emission that significantly slows, it's likely that thankful_for_today or whoever coded up the issuance wanted to make them line up. It may not have been for aesthetic reasons though, it's could've been because they felt the tail emission should kick in sooner and felt that since the XMR will not have a hard limit that the necessity for Monero to hold back coins over a longer period.
It's steeper than bitcoin's because thankful-for-today made it that way. Indeed, if you dig into the bitcointalk forum history, you can find that not many early monero community members were supporting this curve and there was actually discussions about changing the curve.
While this is outside the scope of this particular question, no one actually knows the characteristics of an ideal emission curve. Take for instance Cryptonite (the bitcoin-based coin that uses an innovative accounting system as opposed to straightforward ledgering). This coin has an extremely shallow emission curve - if you mine it now you will get very similar rewards compared to if you mine it in 4 years (or something). This provides no incentive to start mining now - you could wait a couple of years. Thus, there's no incentive to "bootstrap" the network in a speedy fashion. As a result (or its just coincidence), the coin languishes, albeit its obvious advancement of blockchain technology that would completely eliminate any concerns of blockchain scaling, at least regarding the blockchain database.