There's not actually any mechanical value attached to the numbers per se, it's solely based on relative value. There are almost no 1's (I believe Canada, Russia, Mali), so the difference is functionally meaningless on most maps. One problem is that the game reads lakes as coast tiles. But aside from that and a couple of very niche scenarios, coastal civilizations should always get coast, regardless of it being a 2.
Sadly for Spain, which gets coast even with a 3 and actually hates it.
Tell that to the 3 games I have to reroll cause I start in the middle of a continent