Account detail types vs parent/sub accounts

I'm trying to cut down on some of my accounts (due to the new limit on our plan) and wondering what the purpose is for the detail types - like having auto and administration expenses etc. These never seem to be subtotalled in any of the reports .. and seem totally useless.. and we end up creating parent accounts (which we don't really want to post to) but enable us to subtotal. is this pretty much the sum of the situation, or am i missing a way to use the account detail type?