It's important to note that the move to supply certain tanks and IFVs (Bradleys from US, French AMX-30s etc.) is primarily a short to medium term measure.
In the long-term, Ukraine will be equipped with a smaller, more standardised arsenal, but right now it's about restocking the losses they've encountered.
Russia is going to throw thousands of troops (err conscripts), mechanised infantry and tanks at Ukraine when the weather improves, which has to be countered.
The equipment they'll throw likely will be legacy stock (from reserves etc.), yet it'll still have some impact, which means Ukraine will need to counter it.
While a haphazard array of weaponry comes with difficulties, it'll provide the opportunity to hold ground and then, hopefully, go on the offensive themselves.