What's the difference between 74LS00 "gates" and 74LS37 "buffers"?
Yes, the ‘LS37 is a buffer. The high drive figure is used for driving higher fan-out loads. Some other logic gates have equivalent high-drive ‘buffer’ versions. There are also some that are open-collector so that they can be used for wired-or buses and logic. There are still others designed to drive transmission lines.

At any rate, higher current is sometimes needed for large TTL fanout because each driven input presents a DC load that sources some current when the driven signal is low. High drive buffers increase the number of loads that can be reliably driven low.

Buffered outputs are also needed when termination is used to improve signal integrity - especially sensitive signals like clocks.

CMOS and LVCMOS gates also come in ‘buffer’ versions. The game is a bit different. Although CMOS inputs present no DC load, high drive helps CMOS overcome delay due to capacitive loading: it improves switching time. However, like TTL, the high-drive CMOS types help when termination is used.