Actually, you're really misinformed. The SSD does far more than just open apps fast and boot fast. The SSD changes your whole system's performance. Think about everything it really does, then think about how the MBA has limited RAM. Faster ability to read/write allows faster access/ability to page/swap files and etc. The SSD changes the system's performance in MANY ways. Everytime you see a beachball with your HDD, you wouldn't have with an SSD.
People often buy into the misconception that an SSD just makes apps open faster and faster boot, but they're aren't thinking about the big picture and how the system really works.
Actually, you are quite misinformed.
The main advantage for an SSD is no moving parts - which means it has a higher life expectancy and it does not get fragmented.
It will eventually be cheaper to produce too - companies are currently enjoying ripping the consumer off at the moment.
Speed it just a bonus with an SSD - there are still lot's of excellent 7,200RPM drives out there which perform faster than most MLC SSD's, such as the Samsung Spinpoint F3, Seagate Barracuda XT 6GB/s and even the Western Digital Caviar Black series.
Don't get me wrong, I love my RunCore Pro in my Air and it is in a different league to that of the crappy 4,200RPM drive that ships on the base models - even superior to the Samsung SSD that ships with the higher spec Air.
But the fact is until we move onto SLC technology at an affordable price, MLC SSD's are just not special enough.