If we're talking legality then it isn't okay because it isn't safe and you can still be charged. What it comes down to is what's actually a law and what isn't. The law on driving without due care and attention, or the more severe conviction for dangerous driving, would be the likeliest laws to be applied to a driver that caught by the police if they were driving recklessly due to touching a touchscreen infotainment system. As it stands, drivers can be given an on-the-spot fine of £200 and six penalty points if they're caught using a handheld phone while driving. However, in this case, specifically, you have to remember that something has to be an offence to be enforceable and many laws in the UK aren't regularly updated - leaving loopholes. For example, the law - written in 2003 - states that an offence is committed if a driver uses a handheld phone for 'interactive telecommunication' while behind the wheel. As smartphones were not in existence then, the law no longer reflects the reality of mobile phone use while driving. That's why the Government is looking to strengthen the law to ensure drivers can't escape convictions for taking photos/videos, scrolling through playlists or playing games on phones while driving. Similarly, in time, the law may in future reflect using an in-built infotainment screen or sat-nav - but these are already covered by other non-specific road laws and it would be difficult to enforce a law on tech that already exists in cars. On another note, phone use can be tracked, i.e. if you cause an accident the police can check your phone records to see if you were making a call or the like at that time. I don't believe that's possible with infotainment systems unless perhaps you're using your phone via the car's screen (like Apple CarPlay).