Blockchains usually have one or more ‘test-nets’ and 1 ‘main-net’. Developers can get some number of bitcoins, ethereum, or other crypto-coins from ‘faucets’ and then use them in transactions on the ‘test-nets’.
The crypto-coins obtained for use on ‘test-nets’ can not be used on the ‘main-net’ and have no value.
Crypto-exchanges operate with transactions only on the ‘main-nets’ of every crypto-coin that they list.
If a company offers crypto-coins from faucets they may be for use only on test-nets and have no real value.
