The cheaper option - as you apparently discovered with just a little research - is eBay or Aliexpress. Generally much cheaper than Amazon. The penalty? Very slow delivery.
That is indeed how you use them, chained and sharing the same three controlling pins like the MAX7219s.
Advantage? May be a trifle cheaper, but requires a higher voltage supply to operate LEDs in series.
You can, noting that with individual LEDs, not all of the 110 positions in the Word Clock need to be populated.
Disadvantage: Only one LED at any time can be lit by an Arduino Nano at 30 mA brightness. Generally much inferior to using MAX7219s.
Safe? Perfectly good and safe given that you have an adequate power supply. 110 LEDs would be 6.5 Amps at full brightness white but as long as the code never commands that (or the LEDs do not default to that on switch-on which they should not), a couple of Amps should be adequate.
OK, well at 30 LEDs per metre, 11 LEDs is 33 cm width between the outer LEDs, so that is a fairly large clock.