Bitcoin can scale to VISA level transactions[1]. The software is still BETA, the optimizations required for this scalability have not yet been implemented (they are being actively worked on). The primary one is support for pruning the block-chain. This will drastically reduce the current 3GB blockchain size.

You are right though, in it's basic form, Bitcoin will not work for micro-transactions where you want to transfer a few cents a few times a second. However, there are strategies [2] to support some forms of micro-payments.

[1] https://en.bitcoin.it/wiki/Scalability

[2] https://en.bitcoin.it/wiki/Contracts (see example 7)