Before reading this page, users should note that messing with ECDSA private keys is very dangerous and can result in losing bitcoins, even long after the import. It is recommended that outside of self-generated vanity addresses, users should never import (or export) private keys
What does this mean? this is at the wiki. Some other user tried to explain it but I couldnt quite understand and didn't get any answers off anyone else.
It means if you generate your own private keys you need to trust 100% your random source. A weak random number generator produces weak keys which may only be found about out much later on.
I then came across this message:
What does this mean? I've imported the private key just to verify....but I'm wondering if I can recieve bitcoins in the future and also send any transactions when I need to.
I'm a little concerned about the warnings and want to reassure myself
thanks for your patience.
There's a privacy issue and a technical for some, but the main issue was with people spending from Bitcoin Core with imported private keys and then they deleted the wallet.dat file. The change from the spent transaction went to a address generated by Bitcoin Core and when that wallet.dat was deleted the change address and private key for it were lost. There's other solutions now, for example Mycelium offers a way around that and makes spending from private keys easy.