Doing what you described is not as easy as you think, hence not merit-less. Additionally doing such implies, belief in Allah, the hereafter, and acting upon which are all very important.
Indeed, those who believed and those who were Jews or Christians or
Sabeans [before Prophet Muhammad] - those [among them] who believed in
Allah and the Last Day and did righteousness - will have their reward
with their Lord, and no fear will there be concerning them, nor will
People would still do wrong knowing they'll be punished and avoid doing right, knowing they'll be rewarded. It's usually difficult for people to see the light at the end of the tunnel. Especially when the tunnel is 70 years long + time spent in limbo. A lot of Muslims have took bribes regardless of knowing it's haram. Have committed adultery while knowing it's bad for the society and that Allah would punish. Have stole money, etc.
From Imam Ali, Nahj al-balqa: Hikmat 234
إِنَّ قَوْماً عَبَدُوا اللهَ رَغْبَةً فَتِلْكَ عِبَادَةُ التُّجَّارِ،
وَإِنَّ قَوْماً عَبَدُوا اللهَ رَهْبَةً فَتِلْكَ عِبَادَةُ الْعَبِيدِ،
وَإِنَّ قَوْماً عَبَدُوا اللهَ شُكْراً فَتِلْكَ عِبَادَةُ الْأَحْرَارِ.
The worshiper of God-Almighty may be divided into following three groups:
First Group: Consists of those who worship God-Almighty for the sake of eternal rewards, which is like -worshipping of merchants, (for the sake of profit).
Second Group: Consists of those who worship God-Almighty because of the fear of God and retributions, which is like –the worshipping of slaves (for the sake of fear).
Third Group: Consists of those who worship God-Almighty because to express their appreciation and thanks for His bounties and favors which is like the -worshipping of freeman.”