LVM vs 'normal':
Normal partitions are the basic way of separating areas of the system into separate parts, thus giving them their own space. See the cmds
# switch is lowercase L
However, if a partition fills up, it is awkward to extend or re-arrange them
With LVM, you create a disk as an LVM type (type 8e in fdisk) which is called a PV = physical volume. You then group these into a Volume Group (VG), effectively a pool of disk space.
You can then split the VG into LVs (logical volumes), which actually have a filesystem eg ext4 on them.
With this arrangement, you can add more PVs to extend the VG to extend a given LV.
You can also (carefully) remove the PVs and eg re-assign to another VG.
However, unless you have (or will have) a large amt of disks, this is (usually) an unnecessary complication eg for a home system eg if you've only got one or two disks.
NB: its a personal choice at the end of the day.
Note also that that is all LV/VG/PVs are; they do not provide redundancy; for that you need RAID.
FYI: RAID is NOT a substitute for backups!
If you really want to play around, you can create a RAID, then put LVM on top, but is fiddly and coud be tricky to fix if one of the disks does die.
You should read up on RAID and LVM, but you're not likely to need them unless you are at work or have a personal server.