I think looking at plants is not only fascinating, but also helps work out how to grow them. For example, leaf colour, size and feel are big clues as to whether they are mediterranean plants needing dryer sunnier conditions or not - smaller, more leathery and greyer leaves can cope with hotter, dryer conditions. Plants whose leaves are carefully organised not to overlap are often plants who prefer shadier places. Big floppy leaves are unlikely to like windy spots..
And looking at them also leads you to the botanical classification as you've already found! But you can get lost in some of the classification details - this is quite a nice summary
In London. Keen but lazy.