I love this feature so much, I turned it off!
For decades, Excel has been performing default data conversions:
Remove leading zeroes
Keep first 15 digits of long numbers and convert to scientific notation
Convert digits surrounding an E to scientific notation.

New in Insiders beta, Excel will ask if you want to do all three of those things. The first time, I was happy to click Don’t Convert.
But I think the real solution is to embrace all three options and turn all three of them off! They have been annoying us for so long. Why would you want Microsoft to ask, “Hey, should we keep annoying you?”. For me, I am turning all three of these off.

Table of Contents
(0:00) I love this so much, I am turning it off
(1:10) Numbers longer than 15 digits
(1:59) Demo of new box
(2:15) Column not wide enough
(2:51) If you Convert
(3:12) Previous default no warning
(3:45) Remove leading zeroes
(4:14) Custom number format ask?
(4:50) Digits surrounding E
(5:30) Do all 3 or not
(5:45) Don’t Notify checkbox
(6:05) No ask if pasting
(7:13) SUM ignores text
(7:40) Typing data
(9:05) What settings will I use
(10:57) Guerrilla Data Book
(11:28) Nancy Faust
(11:34) Subscribe
(11:42) Retrieve course