Why are many things prohibited in the worldly life though they will be permitted in Paradise?

All perfect praise be to Allaah, the Lord of the worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad, sallallaahu ‘alayhi wa sallam, is His Slave and Messenger.

It must be known that only Allaah The Almighty is the One Who can permit and prohibit things. There is no rule without a rationale that is known to some but unknown to others. Actually, prohibiting and permitting certain things are made a trial in which the person's level of worship and submission is tested. Hence, the believer says "we hear and obey", while the disbeliever says, "we hear and disobey".

Therefore, the believer must not give priority to anything over what is ordained by Allaah The Almighty and His Messenger . Allaah The Almighty Says (what means): {It is not for a believing man or a believing woman, when Allaah and His Messenger have decided a matter, that they should [thereafter] have any choice about their affair. And whoever disobeys Allaah and His Messenger has certainly strayed into clear error.} [Quran 33:36]

It is not for the slave to object to the orders of his Lord or to question reasons for permission and prohibition because Allaah The Almighty says about Himself: {He is not questioned about what He does, but they will be questioned.} [Quran 21:23]

Those who enter Paradise shall have no  obligations, no suffering, and will enjoy the Pleasure of Allaah The Almighty  Who will give them whatever they desire of various kinds of bliss.  Allaah The Almighty will make lawful for them some of the things He prohibited in the worldly life as a reward for their patience and adherence to His Orders. Nevertheless,  there is no comparison between what is available in this worldly life and what is in the Hereafter.

Speaking of the wine in Paradise, Allaah The Almighty Says (what means):

Commenting on the verse [Quran 52:23], Al-Qurtubi states that they do not speak idle talk, nor do they say foul words like those of the drunkards in this life. Ibn ‘Abbaas mentioned that they will not utter falsehood or lies. Mujaahid mentioned that they do not insult one another or commit sins.

Qataadah mentioned that Allaah

The Almighty protected the wine in the Hereafter against the impurities and harm of the wine in this worldly life. He The Almighty removed its harmful effects, such as headache, stomachache,  and loss of mental faculties. Allaah the Almighty informs us that wine in the Hereafter does not make its drinkers utter idle talk or foul words. On the contrary, Allaah The Almighty stresses its beautiful appearance, delicious taste and harmless effects. Allaah The Almighty Says (what means): {White and delicious to the drinkers; No bad effect is there in it, nor from it will they be intoxicated.} [Quran 37:46-47]

Commenting on this verse, Al-Qurtubi quoted Zayd ibn Aslam as stating that the color of the wine in the Hereafter in Paradise is white and  brilliant, unlike the wine of the worldly life which  is unpleasant in appearance;  reddish, blackish, yellowish or brownish which is naturally repugnant to the one with sound taste. Wine in Paradise does not incapacitate the mind. Ibn ‘Abbaas pointed out that wine had four undesirable effects: intoxication, headache, vomiting and excessive urination. However, Allaah The Almighty removed these effects from the wine in Paradise.

Allaah Knows best.