What are the perks of using all UOB products together?

UOB one gives u some perks for multiple relationships with the bank

not advisable to be loyal to one bank only, u should max out the miles earning opportunities by using each banks' specific cards based on your spending habits and any promos available from time to time

From a miles hacking perspective, uob has some good cards for specific spending. Eg 4mpd

UOB preferred platinum for paywave

UOB visa signature for foreign currency spending above s$1k

if you are are a lady- you can select up to 2 categories of spending to earn 4mpd with the uob lady’s Solitaire.
Best of all, uob points pool making it easier to accumulate a critical mass using various cards.

Using the UOB One Credit card along with the One Account means you get to enjoy higher interest rate on your savings with your spending on your UOB One credit card.

That is what the banks want you to do (OCBC 360 account and 365 credit card for example) and they reward with you with higher interest rates.

As long as the benefits maintain, of course you can be loyal to the bank. Eventually when they stop giving the benefits, you should jump when you can get a better deals. Banks are not loyal to you :)

You get to enjoy the entire uob ecosystem of higher interest rate for your saving account as well as upsized credit card rewards. For now UOB has the what suite of banking for retailer. Keep to them as the one bank but should they start taking away the rewards consider greener pastures. It doesn't pay to be totally loyal