I'll start by saying I love BTC but I'm not knowledgeable enough to understand the difference in terms of compatibility between the various BIPs, Bitcoin XT, bigger blocks, etc. However it kind of makes me worried to think that my "traditional" BTC could become useless if another version of the protocol took over. Are my concerns valid? What do we "traditional" BTC holders have to fear? I'd love if you could be as clear as possible. Thanks
you main access to your bitcoins is with the privatekey-publickey pair..
nothing is messing with that. so even if you had a private key from 2009 or made one from any different type of client. it will still work. you will always be able to import your private keys into any version of bitcoin clients
all of the proposed changes are just about letting more transactions occur, and not affecting the privatekey-public key part, so relax