Why is Bitcoin better than other cryptocurrency? If there too many types of such kind of currency, will them be very cheap?

I have 4 BTC and since the current BTC price waves a lot, I am wondering this.

Thanks,
Only time will tell if Bitcoin is the better.
For sure is the first introducing this concept and the biggest market cap at the moment.

Be sure to understand the "cheap" concept. Absolute value means nothing

Suppose at time t1 there are 2 coins and their prices are:
A 1000$, B 1$

After some time this are the coin prices 
A 2000$, B 1.5$

At time t1 coin A was the cheapest!