html - Why are button's discouraged from navigation? -

this may opinionated question, looking around web , seems web developers style <a> tags buttons, rather use specific <button> tag. i've noticeably seen when looking @ navigations

after bit of research, found this:

• buttons not search friendly, since text within invisible search engines.
• buttons harder update links, requiring photoshop , new image every update.
• buttons load more links, making them bad mobile visitors.
• buttons less accessible visually impaired.
• buttons unnecessary, if want use non-standard fonts, tools typekit. ~ quoted here

however, of these 'reasons' seems quite flimsy , answers 'you need photoshop' seem... well... invalid?

so wondering:

is there actual reason why <button> tags aren't used when creating navigation menus, , instead style <a> tags buttons? why aren't buttons norm? not they're made for?

^{* not wish opinion here, nor viewpoint. factual information why case}

after reading on multiple documents posted in comments, seems there clear factual reason buttons not used in navigation bars.

anchor tags

these used when there page redirect or taking user elsewhere on website.

• if navigates, link. use link markup valid hypertext reference

~links not buttons

button elements

these used when want dosomething() not redirecting user. i.e. submitting form / etc.

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the question need ask is:

will control used initiate immediate action or action navigate page?

if answer question first part, should using button element. whereas if latter wishing do, should using a element.

further reading:

• w3.org

• links not buttons. neither divs , spans

• when use button element