as far as i understand Ardor is a platform (parent chain) and Ardor as coin has less features. On the other hand ignis is a child chain in Ardor Platform with lots of features?
so what is the purpose of having Ardor as a coin in the Ardor Platform? Does Ardor miners earn fees or something for every transaction being made in child chains?
You are right with all your statements: Ardor is a token created for "consensus" purposes only. The "minters" earn (pretty expensive) Ardor transaction fees when the "child chain" bundlers bundle transactions into it. "Child chains" are not really blockchains: they are a chained list of transactions called "ChildChainBlock" transactions that are bundled into the main "Ardor" chain.
This "two-tier" design has two purposes:
- first, it allows to create coins (as "child chains") where the transaction fees can be paid in the child chain currency (the concept has been descibed as "Monetary system done right", when it was presented)
- second, it allows a very interesting pruning mechanism. Only the first 1440 blocks of every child chain must be validated by all nodes, the rest is "pruned". That is possible without security drawbacks only because the Ardor main chain (validated completely by all nodes) and its "forgers" are making sure that the ChildChainBlock transactions are legitimate (containing, for example, no double spends).
So the ARDR system is able to process, with the same bandwidth/storage cost resources, about 30 times more transactions than the old Nxt system.
