If you don't use frontpage extensions (who does these days???) then you can probably dump the IgnoreIndex (since apache probably already blocks access to .ht* files.)
the limit lines do exactly as they say, that is, allow everyone to POST or GET. Deny any client header that are PUT or DELETE requests (was that for frontpage extensions???) Either way, I see no issues leaving them or taking them out since PUT and DELETE are not relevant unless you have mod_dav enabled.
The following lines, however...
AuthName www.example.com
AuthUserFile /vti_pvt/service.pwd
AuthGroupFile /vti_pvt/service.grp
...are your password protection. If you use that, you don't want to get rid of these.