I wonder why they picked MyISAM for MySQL, since basically no one sane is using that anymore. It isn't even the default anymore, so that can't be the excuse.
"MyISAM caches index blocks but not data blocks."
"MyISAM caches index blocks but not data blocks."
InnoDB is faster at reads for most workloads on modern hardware. MyISAM has horrible scalability across multiple CPUs. MariaDB recently improved in MyISAM with the segmented key cache, but I haven't seen any results of head-to-head benchmarks since then.