are there any compelling reasons why I should be using LVM?
It's really a personal / system requirements decision.
For example, my (static) workstation. As it is a reuse of (refurbished) hardware of over eleven years of age (the "trailing edge" of hardware) and only has PATA (EIDE) disk interfaces both small (physical) disks are "stitched" together by LVM
to provide one logical, larger, disk.
On the other hand my laptop, just a few months old with one average sized SATA disk, does not use LVM
-- it isn't even installed.
That is just a personal view with a couple of "personal" systems.
Others will be able to explain the many benefits of LVM
when used with a multi-disk server.
40 seconds - Determining IP info for ETH0 and then setting up and connecting to DSL
That seems to be excessive, to me.
My workstation, above, take no more than 5 seconds. It is configured to use a static link between the workstation and the switch / router / modem. (The ADSL link between the modem and the DSLAM is configured as DHCP.)
Please post the output returned by ./getinfo.sh network
, as detailed in How To Provide Information About Your System
. . .