It will make you happier- Denial only makes things better in the short term- it will make you desperately unhappy in the long term because you're only delaying the inevitable and ignoring the reality. The longer you put off the truth the more of a jolt it will be when you face it.
It helps you realise that your partner has faults- You need to recognise that your loved one isn't perfect and that they'll make mistakes at some point. The sooner you pick up on these the better- because it makes you realise that you aren't perfect people nor a perfect couple- but you're able to love each other despite your flaws.
It stops you making excuses for them- Your partner will act in ways you don't agree with and say things you wish they wouldn't but they're in charge of their own actions and what comes out of their mouth- not you. Stop making excuses for them and if they're in the wrong let them apologise- not you.
It puts you at ease- Once you realise that you're not striving for perfection to be equal to your partner, it gives you the lenience to be yourself and accept that you can't be 100% all the time.
It prevents competition- If you put your partner on a pedestal all the time, you will constantly feel inferior to your loved one, which will have a knock on effect on your confidence.
People can see right through it- If you try and cover for your partner, people can see what you're doing from a mile off. It makes your friends and family suspicious of your relationship because every relationship has its hitches along the way.
It's all part of your relationship maintenance- Navigating around your partner's faults and letting them do the same is an integral part of your partnership. It ensures you both know when to give each other space, when to intervene and when to offer words of warning or mediation when you don't agree on something.
You'll run out of conversation- If you agree on everything all the time and don't speak up when you don't- you'll have nothing left to discuss. It's a good thing that your morals and beliefs might align but you may have differing opinions on everyday things that encourage engaging conversation.