Its not just about whether or not its needed now or yesterday, its often a case of future proofing too.
If it costs the same or less per Gb to get higher density ram, then its often worth doing.
In the case of 2x32 Gb, they generally still cost a lot and most motherboards don't support them. 2x16 tends to cost the same or less per Gb than 2x8 does, while also being useful if you only have one or two games that can use it, as well as ensuring you have enough for any upcoming games.
Speed and timings are also somewhat important, and 2x16 has shown to barely be much worse than 2x8, with there being plenty of kits that have the potential for 3600 CL14 or 4000+ CL16.
While there are 2x8 kits that can go higher, they also cost more so whats the point?
Think I read somewhere that G Skill were releasing 2x8 5066 DDR4 for 150 USD, still cant find it anywhere though, and with DDR5 coming out soon it doesn't make much sense to pay any premiums for faster DDR4 right now.