ethereum is expensive too but at least eth transactions are much more faster so you get what you pay for at least but bitcoin it need to improve much more
Bitcoin transactions are also way more secure and the network more protected from malicious attacks
That's what makes bitcoin more popular and most trusted cryptocurrency to invest with.
If you think that bitcoin transactions are slow, just try to become more patient and try to look for greater exchange or software that is also secured.
Malicious attacks are always there that's why you are the one who is responsible with your account and wallet so that viruses will not enter your platform. Also in terms of transactions fees, bitcoin will really have higher transaction fees compared to other coins because the bitcoin community is really huge than other altcoins.