especially because there is no need for a mobile device and they are fairly cheap.
and: because they are cheap, i'm using at least 2 per account/service where such keys are supported.
if i lose the one on my (physical) key-ring, i always have a working replacement at home ... :)
just my 0.02€
idk ... there are lots of companies which offer them ... it depends on your use-case.
in my experience:
for simple account-security - eg. github, google, microsoft, etc. - even older ones work great.
for other purposes you have to look at the feature-list of specific tokens, if they support the necessary security-protocol for your use-case.
personally i have various older & newer models of the companies yubikey - 4 & 5 - and gotrust - idem :)
cheers t.