Is there any particular reason why the Steam application attempts to be so secure? It seems to force you to take more security measures (two-factor authentication, emails confirming all trades, etc) than most banks do.

Is this due to the fact that the Steam software has some inherent security risks associated, or is it just because they want to avoid people complaining that their account was hacked?

Is there any reason that Steam attempts to be more secure than most banks?

Steam has about 100 million users (random link saying they had 75 million almost 2 years ago). If they spend on average $10 per year, we're talking $1,000,000,000 per year - and I'd say that's a conservative estimate (random link saying they had 1 billion in revenue back in 2010). That's the same kind of money small banks deal with.

Then there is almost certainly a large number of low tech attackers. Steam is used by a lot of kids who don't yet have a proper understanding of legality, so at least some of them will try to steal the account of that other kid that smells funny. To be clear: "some" of 100 million is "lots".  These attackers often live in the same town and maybe even saw the other kid typing in the password before, which breaks some traditional safeties based on IP range and passwords. Stolen accounts create customer support costs. Widespread reports of stolen accounts create bad press, which destroys trust. For a digital market, trust is money.

Valve also works with a huge number of partners. These partners can act maliciously and try to break/abuse the billing process, which will directly hurt Steam's reputation and therefore lose Valve some serious money, unless the abuse is detected and dealt with swiftly.

EDIT: 


  [...] enough money now moves around the system that stealing virtual Steam goods has become a real business for skilled hackers [...] We see around 77,000 accounts hijacked and pillaged each month. - 9 Dec 2015 http://store.steampowered.com/news/19618/


So in addition to a large number of low tech attackers, there's a large number of high tech attackers as well.
