Using backpressure in observables of cold type?

Question

Since in Hot Observable , we must use backpressure strategy to prevent from crash but why we use backpressure for example in the following examples which are Cold type:

Example 1

// If we do not use backpressure, the program will crash

        Flowable.interval(1, TimeUnit.MILLISECONDS, Schedulers.io())
                .observeOn(AndroidSchedulers.mainThread())
                .subscribe(new Consumer() {
                    @Override
                    public void accept(Long aLong) throws Exception {
                        // do smth
                    }
                });

Example 2

Flowable.range(0, 1000000)
    .onBackpressureBuffer()
    .observeOn(Schedulers.computation())
    .subscribe(new FlowableSubscriber<Integer>() {
        @Override
        public void onSubscribe(Subscription s) {
        }
        @Override
        public void onNext(Integer integer) {
            Log.d(TAG, "onNext: " + integer);
        }
        @Override
        public void onError(Throwable t) {
            Log.e(TAG, "onError: ", t);
        }
        @Override
        public void onComplete() {
        }
    });