I think altcoins do provide a benefit, bitcoin is not going to be altered that much but with altcoins there is the room to use the blockchain in ways that bitcoin does not, for example proof of stake is one feature which a lot of the altcoins have been using over the past year or so.
Up to now though we haven't seen many altcoins really breaking out on their own, litecoin is the little brother of bitcoin just hanging about and then doge went mental for a while but has settled back down, don't get me wrong there are some altcoins out there that might break on through to the other side but for now they seem to be a way for people to quickly make a profit off of bitcoin.
agree bitcoin also get benefits in altcoin to buy altcoin you will use bitcoin
if there will be no altcoin i dont think bitcoin volume will become like this
someone buy bitcoin just to buy some altcoin and also while other altcoin advertising their coin
bitcoin also get benefits because its only way to buy altcoin
trading flat to bitcoin and vice versa only without altcoin will not make bitcoin price go higher
price of it go lower due to no alternative option to use it