You don't really have a choice in some cases. Coinbase creates new wallets for referrals and maybe other transactions rather than use the existing wallet
I'm not sure what you're talking about. Coinbase does not create new wallets for any transaction. It creates new bitcoin addresses, but all addresses are contained in one wallet.
Fair enough. Wrong word usage but I think thats what the original commentator meant. If not, my fault. That said, unless you have multiple Coinbase accounts, then I fail to see how you could have multiple wallets if they are not synonymous with addresses