Except it doesn’t. There are several ways in which Haiku does things better than Linux such as how it handles low memory and low disk space. But performance of tasks on Haiku can often be and usually is lower than Linux. Especially tasks that are particularly heavy… despite the assertion that drawing with the CPU only is faster, typically equivalent heavy GUI applications are more interactive on Linux, probably as some of the work is delegated to the GPU. Disk, IPC, or memory heavy tasks can also hit slow areas of Haiku. And there have been recent improvements to at least disk and memory on Haiku as of late.
As to why some Linux distros may seem slower on given hardware, it probably comes down to them juts running much more software, and having more optional libraries complied in, if Haiku were running as many daemons and features etc… it would likely be in much the same boat.