Star Trek has a unique history of naming its ships but it was almost completely different.
Star Trek respects traditions. It’s why each flagship of the series is somehow always named The Enterprise, even if its registry details are different. The first Enterprise craft for Starfleet was NX-01. The first Enterprise we saw on television was the NCC-1701.
Future installments would later add minor details, like the NC-1701-A, the NC-1701-B, and so on and so on. This was a way to mark the ship and showcase it as the successor to the previous iteration.
It’s simple, dynamic, and easy to understand and it was almost once completely different. The name of the Next Generation series of ships was going to be NCC-1701-7. The NCC stood for the Naval Construction Contract, while the ship design was apparently the 17th the Federation ever made, and this was the first of the ships built in that design.
Hence 17 and 01.
Yet, according to CBR, when The Next Generation was being developed, the ship was supposed to be NCC-1701-7. However, after viewing Star Trek: IV: The Voyage Home and seeing that the new enterprise’s haul read NCC-1701-A, the TNG Enterprise would undergo some changes to its core concept, where the “-7” was replaced with at first a “G” but then later, with the more well known “D”.
The letter concept was far easier to understand
Star Trek changing from the, seemingly, random number to a coherent lettering idea was the right way to go. While it may not be the most obvious thing to any new fan, once you get into the lore of Star Trek beyond a few series, it becomes quite what ship is which just by the letter.
The Enterprise-A and Enterprise-B were the film ships, while the Enterprise-D was the The Next Generation ship, and the Enterprise-E was the TNG film series ship.
It’s pretty easy to follow along. Granted, the numbering concept may have been just as easy but the lettering gives it a more unique feel.