Does Signal Strength always matter?

[AC Question]

I just got a new router. My old router was an ASUS RT-AC68R Wireless-AC 1900 dual band gigabit router. My new router is a Linksys WRT 3200 ACM Mu-MIMO Gigabit wi-fi router. The only quantitative way I could think of to compare the two was to look at device link speed. I was surprised to see that my old router had about twice the link speed as my new router. For example, on my cell phone, with my old router I was getting a very strong signal at over 700 Mbps, while with my new router, with the phone at the same location, it still shows a very strong signal, but only 433 Mbps. Does this matter or mean the old router was better? BTW, my isp plan is only 50 Mbps. Thanks for any insight.