Why are all text columns shown in tag browser? (And changing column types?)

[ownedbycats]

(sorry for clumsy title, I couldn't fit the one I wanted)

Mostly just curious about why "text, not shown in tag browser" isn't an option except for longtext. My best guess is because hiding categories just makes it redundant.

Also, I'm curious why column types are impossible to change at all. Some of them would obviously cause problems (text=> integer, datetime/boolean<=>anything else, possibly taglike=>text/enumerated), but others seem like they'd be easy to convert (e.g. enumerated=> taglike, text<=>enumerated, rating=>integer).