Miners or at least most of them do not use computers (CPUs) to mine anymore, they rather use GPUs or ASICs.
Bitcoin miners can only use the special machines called ASICs (Application Specific Integrated Circuit) to mine bitcoin and nothing else since anything else including a big GPU rig can not produce nearly enough hashrate compare to an ASIC.
Altcoin miners on the other hand can use either CPU or GPU or ASIC to mine their altcoin depending on what the coin is.
Yes, although we can do mining using the CPU, it will not generate Bitcoin. I've tried it, the computer melted. For mining altcoins, can use the CPU or GPU. But also quickly damage the motherboard. If it's a professional miner, they no longer use a standard computer, because the expenses are greater than the income generated by mining. Especially the problem of electricity costs.