1.Top-level performance:
Turn-based means everything is not reacting after the turn. i.e. rendering, sounds and dynamic effects are one-time expense. Raytracing everything is possible. Much higher quality of everything. Time to procedurally generate stuff.

2.Actual long-term strategy with discrete steps: chess allows planning because steps are discrete and not dependent on timing(except maybe a timer for 1minute per turn, so a player can't drag a game forever).
Discrete starcraft would allow novices to copy openings and execute them flawlessly, without speed requirements(300 actions per minute).
It also allows composing openings and evaluating each strategy without external interference.
Discrete diablo-clones/ARPG would need something like "stop time" after each attack, i.e. you attack->monsters counter-attack->their attack ends-> time freezes until you act.
So the gameplay can be seamless like real-time and not "select options for next turn" cludges typical of turn-based RPG.

3.More options for combat mechanics:
Discrete mechanics allow "turns" to be considered as time units and modifiers can affect them instead of time.
In RPGs,DPS becomes obsolete. Players can prepare custom attacks.
In RTSs, first attack become critical too, dps-based "strategies" replaced by micro-management and unit selection.
Micromanagement becomes much easier in all genres you have time to craft any tactics.

4.Balancing becomes easier:
Players no long have timing advantages or advance their skill due fast reaction.
Turn-based design means any automated scripts/macros/bots will not gain superhuman advantage by being faster.
Everything is much easier to compare within discrete steps: turn-based interaction are simpler by design.

5.Less demanding skills from player base:
Elite twitch skills are not required anymore. Casual gamers can easily try anything and replicate any tactic. Game can be "paused" at anytime by just not doing a turn.
Any urgent phonecalls/emails can be answered immediately. Low-maintenance gaming which can last as long as players want(with no time limits per turn), also low-impact on servers(idle state).

6.Discrete turns can be analyzed and understood much easily than chaos of real-time gaming.

7.Games can be saved and reloaded at any step easily;i.e. you can time-travel to any part of the game and replay it within the game.

8.Real-time actions can be separated into discrete chunks:i.e. you don't need to tell a Starcraft drone to move 50 times. You can order it to move once, and each turn it will move one step.
Micromanagement isn't mandatory.